on the abit nf7-s i can go as high as 99mhz for the AGP i'm not really sure on this i have it clocked to 75mhz now what are some opinions and this just helps faster data rate?
agp mhz
- Thread starter XxervioCSO
- Start date
If possible, set your agp aperature rate at 1/4 the value of your onboard video card memory. If it's 64 megs, then set the agp at 16. This is from the instructions of my nvidia chipset video card. Setting it higher won't speed things up.
well it seems like if i set the aperature to 128 i get more FPS then i do when i set it at 64 i get about 5fps less 
i know not much.
i have a gforce 5200 128 meg
i know not much. i have a gforce 5200 128 meg
True, but as the AGP bus rises, more is less. I too, at lower speed get better FPS with higher AGP, but as the bus freq. rises so does instability. Somethings got to give.
If you want to run way higher than spec AGP, then a smaller aperture really helps to stabilize. The speed of the bus more than offests the hit of less available memory to work with. As I'm typing, my AGP bus is at 87 Mhz. To stabilize it, I run a 32 Mb aperture. At 82 Mhz, I can run a 256mb aperture without a hitch. By the time my AGP bus is at 90 Mhz, I have to run a 16mb aperture. Going lower than that crashes badly in games. 16mb would be the minimum anyways (2mb minimum reserved for AGP, multiplied by two for minimum call by the AGP, then add 12 mb as per spec = 16mb). As long as you are above 16mb, you will be fine.
If you want to run way higher than spec AGP, then a smaller aperture really helps to stabilize. The speed of the bus more than offests the hit of less available memory to work with. As I'm typing, my AGP bus is at 87 Mhz. To stabilize it, I run a 32 Mb aperture. At 82 Mhz, I can run a 256mb aperture without a hitch. By the time my AGP bus is at 90 Mhz, I have to run a 16mb aperture. Going lower than that crashes badly in games. 16mb would be the minimum anyways (2mb minimum reserved for AGP, multiplied by two for minimum call by the AGP, then add 12 mb as per spec = 16mb). As long as you are above 16mb, you will be fine.
well it seems like if i set the aperature to 128 i get more FPS then i do when i set it at 64 i get about 5fps less i know not much.
i know not much.Like I said, more aperture is better, to a point.
As the AGP bus frequency rises, so does the instability. In short, lower the aperture to lessen the strain if you see problems cropping up. Until it causes issues, go for the maximum available in BIOS. When lowereing the aperture, Do not go below 16mb though as that will also cause issues with most modern mobos.
As the AGP bus frequency rises, so does the instability. In short, lower the aperture to lessen the strain if you see problems cropping up. Until it causes issues, go for the maximum available in BIOS. When lowereing the aperture, Do not go below 16mb though as that will also cause issues with most modern mobos.
Me too. I've seen benchmark tests at different apertures that are faster, and some slower depending on hardware.
Generally, so long as the card is fast, theres little to be gained by going over 128mb, especially if you don't have oodles of RAM. The AGP bus can use between 16mb, and the limit you set where usage is concerned on a modern mobo. If you have a fast card, and a high data transfer rate, then 128 or lower is a good stable setup. 256 is generally for games with buttload of data to move, or 3D rendering applications. Larger apertures have the possiblity to stress subsystems more, but at stock bus speeds, it will not be a problem. The problem comes up at out-of-spec, (read overclocked) bus speeds. All sorts of mayhem can occur. If you shrink the aperture, the elevated data transfer rate from overclocking makes up for it, so the performance hit is very small.
Generally, so long as the card is fast, theres little to be gained by going over 128mb, especially if you don't have oodles of RAM. The AGP bus can use between 16mb, and the limit you set where usage is concerned on a modern mobo. If you have a fast card, and a high data transfer rate, then 128 or lower is a good stable setup. 256 is generally for games with buttload of data to move, or 3D rendering applications. Larger apertures have the possiblity to stress subsystems more, but at stock bus speeds, it will not be a problem. The problem comes up at out-of-spec, (read overclocked) bus speeds. All sorts of mayhem can occur. If you shrink the aperture, the elevated data transfer rate from overclocking makes up for it, so the performance hit is very small.
Jeff7181
Lifer
- Aug 21, 2002
- 18,368
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Run nVidia's Last Chance Gas station on a 128 MB card with a 64 MB aperature... slow as molases in january. Run it on a 128 MB card with a 128 MB aperature... still slow, but about 2-3 times faster than with a 64 MB aperature. This is because the textures are HUGE and it needs more than 128 MB of memory.
Yup, you are right.
Now increase the FSB, RAM freq. and the AGP data transfer rate by, say..... 20 percent. You'll get more FPS than increasing the AGP aperture, even if you decrease the AGP aperture for stability, because of the increased overall speed of the systems involved.
It's kinda like having either ten people at a time loading a truck, or two, super speedy guys moving at five times the speed. Is there any difference in time spent to do the work? No. If the speedy guys can only move two at a time, but at five times the velocity, then they will finish at the same time as the ten normal guys.
AGP is the same. High aperture, or raw speed. The end result is the same. The ultimate setup would be to find a system that is stable at high aperture, and high AGP bus speeds.
Now increase the FSB, RAM freq. and the AGP data transfer rate by, say..... 20 percent. You'll get more FPS than increasing the AGP aperture, even if you decrease the AGP aperture for stability, because of the increased overall speed of the systems involved.
It's kinda like having either ten people at a time loading a truck, or two, super speedy guys moving at five times the speed. Is there any difference in time spent to do the work? No. If the speedy guys can only move two at a time, but at five times the velocity, then they will finish at the same time as the ten normal guys.
AGP is the same. High aperture, or raw speed. The end result is the same. The ultimate setup would be to find a system that is stable at high aperture, and high AGP bus speeds.
Jeff7181
Lifer
- Aug 21, 2002
- 18,368
- 11
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Actually the aperature has nothing to do with speed. The aperature is only the amount of physical RAM available for use as texture memory if the video card doesn't have enough onboard. It doesn't effect stability or bus speed or anything else. All it does is let the video card use that much physical memory for texture memory.
Never said the aperture had to do with speed, just that if the AGP bus is transferring data at a super rapid rate, then you won't need as much aperture (System RAM is SLOW). The lessened strain on all the related subsytems makes them more stable. It also allows more RAM available to the rest of the system at any given moment.
Your statement is not entirely accurate. You can set the AGP aperture to as low as it goes, and it will still use RAM. The aperture isn't just for textures. First, AGP aperture is also used for certain index/vertex buffers. It won't automatically use system RAM even if you set it to 256 Mb either. It merely reserves the address, preventing the system from using that address for anything else. An advantage to keeping it small is to keep the GART table at a manageable size.
The tighter the system timings, and the higher the FSB/PCI/AGP the more of an issue this can create as the call could time-out, or the system could be forced to swap because it is waiting for the dead slow system RAM. This could kill kill FPS as sure as it snows in Maine.
AGP only uses RAM for textures when the request is in excess of all available resources. It will use only what is necessary up to the limit of the aperture.
Lastly, system RAM is dead slow when compared to VRAM, so it makes sense to use the absolute minimum of system RAM in any given situation. That doesn't mean that lower is better, just that lower to a point is better where system RAM v. VRAM is concerned. The more on-board VRAM, the smaller the aperture can be, and get the exact same, (or faster) results.
Despite this, having a card with 256 mb on-board will still require a 16mb minimum aperture because the smallest setting is 2mb. AGP spec requires a (x2) call plus 12mb. 2 x2 +12 =16mb.
Your statement is not entirely accurate. You can set the AGP aperture to as low as it goes, and it will still use RAM. The aperture isn't just for textures. First, AGP aperture is also used for certain index/vertex buffers. It won't automatically use system RAM even if you set it to 256 Mb either. It merely reserves the address, preventing the system from using that address for anything else. An advantage to keeping it small is to keep the GART table at a manageable size.
The tighter the system timings, and the higher the FSB/PCI/AGP the more of an issue this can create as the call could time-out, or the system could be forced to swap because it is waiting for the dead slow system RAM. This could kill kill FPS as sure as it snows in Maine.
AGP only uses RAM for textures when the request is in excess of all available resources. It will use only what is necessary up to the limit of the aperture.
Lastly, system RAM is dead slow when compared to VRAM, so it makes sense to use the absolute minimum of system RAM in any given situation. That doesn't mean that lower is better, just that lower to a point is better where system RAM v. VRAM is concerned. The more on-board VRAM, the smaller the aperture can be, and get the exact same, (or faster) results.
Despite this, having a card with 256 mb on-board will still require a 16mb minimum aperture because the smallest setting is 2mb. AGP spec requires a (x2) call plus 12mb. 2 x2 +12 =16mb.
I have always heard OCing the AGP frequency can risk killing your video card? Is that true or is it just a myth?
Whenever you overclock, you take a risk of damaging components. My take is that with proper knowledge, cooling, timings, and good hardware, you can minimize risks. Notice that I said minimize....anything will have risks as you raise the frequncy beyond the design parameters. If you don't understand the risks, you shouldn't take them.
In a nutshell... Until you can afford to pay, you can't afford to play.
That being said, the risk rises as the frequency rises. I have run as high as 101.5 Mhz AGP bus for extended periods (not adviseable). I gained no real world speed at that level, so dropped down until I met speed V. diminishing returns point. I't makes no sense except as bragging rights to go beyond the point that you show appreciable gains in performance of some type. I'm a gamer, so FPS is the be-all for me. When I push the system over 185 Mhz FSB (92.5 Mhz AGP on my KR7A-133), the gains are so little that it's not worth the heat and noise of the fans turned up (to me at least). To each their own though. Just know the risks, and be able to pay to play if the need arises.
In a nutshell... Until you can afford to pay, you can't afford to play.
That being said, the risk rises as the frequency rises. I have run as high as 101.5 Mhz AGP bus for extended periods (not adviseable). I gained no real world speed at that level, so dropped down until I met speed V. diminishing returns point. I't makes no sense except as bragging rights to go beyond the point that you show appreciable gains in performance of some type. I'm a gamer, so FPS is the be-all for me. When I push the system over 185 Mhz FSB (92.5 Mhz AGP on my KR7A-133), the gains are so little that it's not worth the heat and noise of the fans turned up (to me at least). To each their own though. Just know the risks, and be able to pay to play if the need arises.
How So? Please explain your take on how the AGP bus/data rate isn't important when allocating memory for AGP aperture size?
No, it's not totally like that, but the faster timings available would speed transaction and throughput times.
Maybe I?m scattered these last couple of posts?..
The GART (located in system memory) has to translate all the memory pages that are allocated during AGP memory initialization. These are set up as 4k non-contiguous memory, and the GART has a job to make it appear to be contiguous. It does this using a remapping table, and translates virtual addresses into physical addresses. It is not fast, and in comparison to VRAM operations, it is slow. Also, the larger the GART, the more time it takes to reference. The Aperture is a block of reserved and contiguous memory space located above the top of the memory (by specs). It is used like system memory, and it?s where the virtual addresses are translated into physical addresses. These addresses are then used to access the AGP memory, the frame buffer, and main memory. This information is not stored here, just translated, sent out. Access to the AGP memory and graphics controller is through this reserved amount of system memory.
In games with large textures, the throughput will always be faster with a higher AGP bus. Notice I said throughput, not caching. The latency of the AGP request will be reduced, and the fewer AGP requests per MB help out as well. Smaller textures need faster latencies, which are also helped by an elevated system bus.
As you see, the aperture is just working space, not storage space, so the speed off operations as well as the number of operations allowed to take place in system memory should be considered when setting the Aperture size. Fewer operations, done faster are always a good thing. You want the fastest operations, with the highest throughput, not just the highest bandwidth.
In system RAM, faster timings at any set frequency always yield better FPS than slower RAM timings because it is able to perform the action faster.. In AGP usage, the faster the timings and throughput (and not just bandwidth), the better the FPS as well. Limiting available bandwidth to prevent system management is mostly good, because Windows (notably XP), has a mind of it?s own as far as settings are concerned, and often does things that are not in the best interests of overclocked busses.
I kinda wandered here, so sorry.
Maybe I?m scattered these last couple of posts?..
The GART (located in system memory) has to translate all the memory pages that are allocated during AGP memory initialization. These are set up as 4k non-contiguous memory, and the GART has a job to make it appear to be contiguous. It does this using a remapping table, and translates virtual addresses into physical addresses. It is not fast, and in comparison to VRAM operations, it is slow. Also, the larger the GART, the more time it takes to reference. The Aperture is a block of reserved and contiguous memory space located above the top of the memory (by specs). It is used like system memory, and it?s where the virtual addresses are translated into physical addresses. These addresses are then used to access the AGP memory, the frame buffer, and main memory. This information is not stored here, just translated, sent out. Access to the AGP memory and graphics controller is through this reserved amount of system memory.
In games with large textures, the throughput will always be faster with a higher AGP bus. Notice I said throughput, not caching. The latency of the AGP request will be reduced, and the fewer AGP requests per MB help out as well. Smaller textures need faster latencies, which are also helped by an elevated system bus.
As you see, the aperture is just working space, not storage space, so the speed off operations as well as the number of operations allowed to take place in system memory should be considered when setting the Aperture size. Fewer operations, done faster are always a good thing. You want the fastest operations, with the highest throughput, not just the highest bandwidth.
In system RAM, faster timings at any set frequency always yield better FPS than slower RAM timings because it is able to perform the action faster.. In AGP usage, the faster the timings and throughput (and not just bandwidth), the better the FPS as well. Limiting available bandwidth to prevent system management is mostly good, because Windows (notably XP), has a mind of it?s own as far as settings are concerned, and often does things that are not in the best interests of overclocked busses.
I kinda wandered here, so sorry.
Jeff7181
Lifer
- Aug 21, 2002
- 18,368
- 11
- 81
Nice in depth explanation... but it doesn't have much to do with the topic =) I know it's easy to go off on a tangent... but as you said before, there will always be some memory devoted to the necessary operations... when you set the AGP aperature in the BIOS, you're more or less telling it how much it can use for texture memory. So no matter how much you adjust the aperature, you won't take memory away from those necessary operations... so the point you're making is moot.
Overclocking the AGP bus is basically useless unless you have an old motherboard with a new video card that's starved for bandwidth because of the old motherboard that may only support 1X AGP or 2X AGP. Then, overclocking will provide more of the necessary bandwidth.
But all that is completely unrelated to the size of the aperature. I've kept my AGP aperature at 64 MB all the time, and the ONLY time you need to change it is if you run a game or application that requires more memory than you have on your video card. For example, nVidia's Last Chance Gas Station demo is designed to run on a video card with 256 MB of RAM. Mine has 128, plus the 64 MB aperature... part of which is being used for the things that maluckey explained. So even setting it to 128 doesn't help because a portion of that is already being used... so I have to set it to 256 to run that demo. But I keep it set at 64 because there's no other game that needs more than what my video card has.
So... ONLY attempt overclocking the AGP bus if your motherboard isn't capable of 4X AGP and you have a video card that is.
And ONLY change the AGP aperature if your video card doesn't have a sufficient amount of memory to run the applications you're trying to run.
Overclocking the AGP bus is basically useless unless you have an old motherboard with a new video card that's starved for bandwidth because of the old motherboard that may only support 1X AGP or 2X AGP. Then, overclocking will provide more of the necessary bandwidth.
But all that is completely unrelated to the size of the aperature. I've kept my AGP aperature at 64 MB all the time, and the ONLY time you need to change it is if you run a game or application that requires more memory than you have on your video card. For example, nVidia's Last Chance Gas Station demo is designed to run on a video card with 256 MB of RAM. Mine has 128, plus the 64 MB aperature... part of which is being used for the things that maluckey explained. So even setting it to 128 doesn't help because a portion of that is already being used... so I have to set it to 256 to run that demo. But I keep it set at 64 because there's no other game that needs more than what my video card has.
So... ONLY attempt overclocking the AGP bus if your motherboard isn't capable of 4X AGP and you have a video card that is.
And ONLY change the AGP aperature if your video card doesn't have a sufficient amount of memory to run the applications you're trying to run.
Strange, in UT2003, I have at least fifty benches that show contrary to this statement (motherboard and vid card set to set to AGP 4x thank you). They show faster speeds as the PCI/AGP/RAM speeds rise, and the Aperture decreases. I have another thirty or so from IL-2 Sturmovic to back them up. True, these are not games designed for 256 mb cards, but are currently about the most stress that you can put on a system as far as games. You have no overclocked benches (that you mention). Please try your benchmark while 20 percent overclocked, and post the results.
It wouldn't surprise you in the least to know that what you say floes in the face of logic? A bus at a higher frequency, can transfer more data at any given setting, than a lower frequency bus set the same. Period.
Change it from what to what? The system will still run any application with a 16mb Aperture, regardless of texture size or quantities. It will also run any application at 32 mb Aperture, albeit with more info in slower memory. In this case, it's less information left to wait in line for the much faster VRAM. Find the happy place where less is sent to RAM, but still not waiting more than the time spent in system memory, and the system speeds up. Let's say that data has to wait say.002 seconds (an arbitrary number) for system RAM to perform a certain task. The same task can be performed by the VRAM in .0011 second, but has to wait .0011 seconds to access the VRAM (because of a pending operation), the total is .022 seconds. The two operations in VRAM would be just as fast a sending one to system memory. Why in this case, or in cases where the operations, including wait time would be faster, would you want to send ANYTHING to system memory?
When you get to the point where when waiting on the VRAM takes more time than sending the data to system memory, you should increase your Aperture, and not before. On a non-overclocked setup, the penalties are much less than at higher bus speeds, and in some setups, may have little real world penalties (if any) for large AGP Apertures. On an overclocked bus, it makes sense to run as small of an Aperture as you can, before you degrade the performance. Now, AGP 3.0 allows more going on at the same time, but the basic operations are very similar.
I have better things to do than argue one sidedly. I can post as many benches as you'd like at AGP bus speeds from 66 Mhz, up to 90 Mhz, to disprove that a higher Aperture is always better.
Later,
Mark
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