All these websites say things such as "supports DDR400" or "FSB 200". Howerver, when I read all these explanations about the integrated memory controller of the AMD64s, they never mention how the motherboard factors into the equation. It seems like it shouldn't, it's up to the CPU's IMC as to what memory speeds you can run at. I wouldn't mind spending so much on the A8N-SLI if I knew that I could, at a later time, upgrade to a AMD64 with a higher IMC speed and faster memory without having to ditch my mobo. So why do these websites still say that the motherboard only supports DDR400 or has a FSB of 200??? Basically my question is, at a later date, could I install a AMD64 with, say, support for DDR500 and some DDR500 memory without any gripes from the motherboard?
amd64 mobos and memory speeds
- Thread starter reydix
- Start date
Hmmm... 40 views and no replies. I was planning on going to Fry's Electronics anyway, I guess I'll ask someone there and post what I find out here.
Why does everyone keep saying bump after their first post? But I am confused on the whole state of FSB and all. I'm just now getting ready to make the jump from Athlon XP to Athlon 64. But anyway:
What is the actual bus speed of an Athlon 64 board. To give a little more detail, i'm looking at getting an Athlon 64 3200+ with the new 90 nano core. I thought it was 400Mhz, yet I keep reading people using DDR4000, which I think goes at 500Mhz. I'm looking into OC'ing my proc by the way. So which speed of RAM should I use?
What is the actual bus speed of an Athlon 64 board. To give a little more detail, i'm looking at getting an Athlon 64 3200+ with the new 90 nano core. I thought it was 400Mhz, yet I keep reading people using DDR4000, which I think goes at 500Mhz. I'm looking into OC'ing my proc by the way. So which speed of RAM should I use?
Ok here ...
FSB on the A64 platform is now called HTT, the terms are still used interchangably in fact. Motherboards like the DFI Lanparty UT 250gb based on the nf3 chipset allow you to use what's called a memory diveder. this is handy because all A64 (with the excpetion of the FX series) have their multipliers locked past the multipler they rated at. For instance my 3200+ 754 is locked with a multi of 10 so, unlike the XP series, I cannot really use the multiplier to assist in the OC'ing of the proc. Therefore that leaves only the FSB/HTT to fiddle with.
You're correct in stating the memory CONTROLLER is on the CPU which reduces the sum length of channels involved with exchanging data between your CPU and your RAM, but that does not change the fact that your RAM is obviously not located on your CPU. This means that your RAM is still going to be a limiting factor in how high you can OC. The integrated memory controller on the AMD64 allows the FSB/HTT to reach, in many cases, 260Mhz or higher, but can your RAM handle that speed? 260Mhz in DDR terms is 520Mhz, which requires 25% increase over typical PC3200 (200Mhz, or Double Data Rate 400Mhz) RAM. That's why many RAM manufacturues sell RAM that is rated UP TO PC4400 (Im probably wrong but I think that's somewhere around 260Mhz), etc. The thing is, you don't need your RAM to run as fast as your FSB/HTT and that is why we have a memory divider.
The memory divider allows us to greatly increase the FSB/HTT of our CPU's allowing this route for AMD64 OC'ing without taxing the hell out of our RAM. For instance if you bumbped up your FSB/HTT to 250Mhz with a CPU multipler of 10 that would put your CPU to 2.5Ghz. Pretty straightforward. If you wanted your PC3200 RAM to STAY at PC3200 speeds, you would set your memory divider to a ratio of 5:4 (ratio translates to 5=cpu 4=RAM.) Now you have a 2.5ghz CPU with RAM running at a comfortable 200 Mhz / DDR 400Mhz.
You might be wondering what the penalty of using the memory divider is, and here's the great part; it's not very insignificant. Anyone on here will tell you the forum member Zebo wrote up an excellent article he posted here about the significance of the memory divider that you might want to read as it verifies rather indisputedly the claim.
Regardless, many still want inrease their memory bandwidth and therefore try achieve their hufe FSB/HTT OC's with a 1:1 divider; meaning, their RAM is running at full speed with their FSB/HTT. This requires the type of RAM I spoke of earlier (the PC4400 type stuff) and WILL improve your memory bandwidth. People like myself however don't believe the performance returns justifies the expense of premium quality RAM when , for half the price, you can get decent value RAM that will enable your PC to run within 3% toi 5%.
Now as far as your A8N is concerned, I have no experience with and have not ready anything about it so someone elese would have to answer whether or not it can support extrememly high FSB/HTT speeds. I would suspect it can however, in which case you can feel free to purchase better RAM at a latter date, drop you CPU multiplier a bit and max out your RAM and FSB/HTT to maximize your RAM bandwidth while retaining whatever the max OC is for your CPU.
Hope this helps
John
FSB on the A64 platform is now called HTT, the terms are still used interchangably in fact. Motherboards like the DFI Lanparty UT 250gb based on the nf3 chipset allow you to use what's called a memory diveder. this is handy because all A64 (with the excpetion of the FX series) have their multipliers locked past the multipler they rated at. For instance my 3200+ 754 is locked with a multi of 10 so, unlike the XP series, I cannot really use the multiplier to assist in the OC'ing of the proc. Therefore that leaves only the FSB/HTT to fiddle with.
You're correct in stating the memory CONTROLLER is on the CPU which reduces the sum length of channels involved with exchanging data between your CPU and your RAM, but that does not change the fact that your RAM is obviously not located on your CPU. This means that your RAM is still going to be a limiting factor in how high you can OC. The integrated memory controller on the AMD64 allows the FSB/HTT to reach, in many cases, 260Mhz or higher, but can your RAM handle that speed? 260Mhz in DDR terms is 520Mhz, which requires 25% increase over typical PC3200 (200Mhz, or Double Data Rate 400Mhz) RAM. That's why many RAM manufacturues sell RAM that is rated UP TO PC4400 (Im probably wrong but I think that's somewhere around 260Mhz), etc. The thing is, you don't need your RAM to run as fast as your FSB/HTT and that is why we have a memory divider.
The memory divider allows us to greatly increase the FSB/HTT of our CPU's allowing this route for AMD64 OC'ing without taxing the hell out of our RAM. For instance if you bumbped up your FSB/HTT to 250Mhz with a CPU multipler of 10 that would put your CPU to 2.5Ghz. Pretty straightforward. If you wanted your PC3200 RAM to STAY at PC3200 speeds, you would set your memory divider to a ratio of 5:4 (ratio translates to 5=cpu 4=RAM.) Now you have a 2.5ghz CPU with RAM running at a comfortable 200 Mhz / DDR 400Mhz.
You might be wondering what the penalty of using the memory divider is, and here's the great part; it's not very insignificant. Anyone on here will tell you the forum member Zebo wrote up an excellent article he posted here about the significance of the memory divider that you might want to read as it verifies rather indisputedly the claim.
Regardless, many still want inrease their memory bandwidth and therefore try achieve their hufe FSB/HTT OC's with a 1:1 divider; meaning, their RAM is running at full speed with their FSB/HTT. This requires the type of RAM I spoke of earlier (the PC4400 type stuff) and WILL improve your memory bandwidth. People like myself however don't believe the performance returns justifies the expense of premium quality RAM when , for half the price, you can get decent value RAM that will enable your PC to run within 3% toi 5%.
Now as far as your A8N is concerned, I have no experience with and have not ready anything about it so someone elese would have to answer whether or not it can support extrememly high FSB/HTT speeds. I would suspect it can however, in which case you can feel free to purchase better RAM at a latter date, drop you CPU multiplier a bit and max out your RAM and FSB/HTT to maximize your RAM bandwidth while retaining whatever the max OC is for your CPU.
Hope this helps
John
Because when looking at all the motherboard threads, the one with the latest reply is listed first. So, if no one has replied to your thread and are replying to other threads, those threads are going to be above yours on that list. My thread fell off the first page of threads, and no one reads or replies to those, so I replied to my own thread to bump it back up to the top. It's kinda selfish, but hey it worked!
Anyway, thank you very much for your replies, however I guess my question wasn't very clear. Let me clarify:
Right now I want to buy the A8N-SLI, dual DDR400 memory, and a reasonably priced AMD64 that supports DDR400. Which, as far as I can tell, will work just fine. However, lets say a year from now, DDR500 comes out and an AMD64 comes out with an integrated memory controller that supports DDR500. Can I plop those in my motherboard and have them run at 500? Or do these AMD64 motherboards still have some control over memory speed, despite the memory controller being on the CPU? Because when reading about the Integrated Memory Controller, it sounds like its totally seperate from the northbridge, therefore the motherboard isn't a factor when upgrading to faster memory. However, all these motherboard specs still list what memory they can support as if anything faster than that won't work. Is there something I'm missing?
I don't foresee DDR500 ever becoming an official spec. If more bandwidth is needed, AMD will probably move to DDR2 or DDR3 (when the technologies have proven themselves).
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