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How bad does running memory at 135mhz hurt performance?

G

Gumby84

Member
I've got a Winchester 3000 running at 2430ghz, but my memory is some sucky Hynix 3200...so I have to run it at 100mhz. My question is how bad will this hurt my performance for gaming until I can get some good memory? Should I just clock the cpu down and run the memory higher? Thanks guys.
 
I'm guessing it would hurt performance, but how much, I have no idea. I would try and change the memory for some known good RAM, and if it still doesn't work, it's going to be your mobo.
 
Originally posted by: Azzy64
100mhz?? um, try a different divider dude.
Click to expand...


yup. Gumby84, sounds like you haven't been using good settings. drop the divider, keep the FSB, and set the memory limit to 166MHz (5:4). If your memory doesn't reach 400, add a few more MHz to the FSB.
 

2430 / 9 = 270 / 2 = 135 MHz which is not equal to 100 MHz, and is significantly higher than half it's rated speed. So those talking about half it's rated speed clearly don't know what they're talking about.

To the OP, you should at least be able to run at 133, which will put you at ~174 MHz. This is the closest you can get and still be below your rated speed. If your memory cannot run at 174MHz at it's rated latencies for PC3200, you should be able to return it without issue, because it's not performing as it should.

Setting to 166 MHz would be a significant overclock, as that would be 221 MHz so it's possible you wouldn't be able to make that, but it doesn't hurt to try.

You never mentioned latencies. What are it's rated latencies at PC3200 and what latencies were you trying to run?
 
Hey Concillian, when the OP says he "has to run it at 100mhz", that's half it's rated speed. If it isn't running at 100mhz, then it's the OP who clearly doesn't know what he's talking about, not those who responded to him. Was it too much trouble to read the OP?


100mhz?? um, try a different divider dude.
Click to expand...

That's what the first 5 responses meant. 😀
 
I read the OP, but even a basic knowledge of how the A64 and RAM interact would tell you that with his setup (9x270 = 2430MHz) he cannot possibly be running 100 MHz RAM speed.

While I agree that the OP could have been more specific, it is excusable that someone posing the question may not know any better.
 
I there Concilian, sorry for this noob question, but i don't know sh** about A64 configs.

Could you explain more how you got those numbers ?!?

TIA
 
1) RAM speed is always an integer divided by the CPU speed. This is to alleviate problems with the memory frequency un-synced with CPU frequency.
2) A value listed in BIOS for RAM speed really means that ratio when the CPU is at it's default speed (default is for 200 MHz RAM)

So when you put 100 MHz in BIOS that is really saying "no faster than 1:2 ratio" It will use whatever integer value is closest to 1:2 without going over 1:2. 1:2 always yields an exact speed, but the other dividers do not always.

To use the example speed and multiplier he has 9x270 = 2430:

setting 200 = 1:1 = RAM speed of 270 (that one should be obvious)
setting 166 = 5:6 = 2430/11 = RAM speed of 220.9 (270 * 5/6 = 225)
setting 133 = 2:3 = 2430/14 = RAM speed of 173.6 (270 * 2/3 = 180)
setting 100 = 1:2 = 2430/18 = RAM speed of 135 (270 * 1/2 = 135)

What I don't get is why BIOS's have to be so cryptic. Why not just give us control over the integer dividers and let us use whatever suits us best? I bet there will be a board that does this eventually, but who knows when eventually will be.

If we were allowed that kind of freedom, we could choose something like CPU speed divided by 12, and in that case 2430/12 = 202.5. I sure hope most PC3200 can do that. Then the people with killer RAM could choose 10,9, or even 8 if they had crazy fast RAM.
 
Thanks for your reply Concillian. Yes it is set to 100 in the bios and running at 135....thus the only way I can reach stable speeds of 2430 on the winchester 3000. So back to my question how bad does this hurt my performance in gaming? Should I just lower the cpu freq and run the ram faster?
 
a quick way to do speeds too is to simply determine the % overclock of the FSB (eg. 240 is a 20% overclock), then apply the increase in % to the memory limit.
example:
100MHz +20% = 120MHz or DDR240
133MHz +20% = 160MHz or DDR320
166MHz +20% = 200MHz or DDR400

in OPs case, he claims to be running a FSB of 270 (that is awfully high...) this forces him to set a memory limit of 100MHz.
270MHz is a 35% overclock (=70/200)
100MHz + 35% =135MHz or DDR270
 
It depends on the game. Look at the AT memory reviews for some insight here, as they have gaming performance benchmarks with RAM speed changes at the same CPU speed. It will hurt performance more at lower frequencies. If you have a CPU/RAM dependent game, I expect the difference to be pretty significant. Obviously if it is not CPU/RAM speed dependent you won't have much of a difference. Most people run games in modes that are NOT CPU/RAM dependent, but video card dependent.

I don't understand, you can get 200 MHz with the CPU frequency lower? That doesn't make sense. The two should be unrealated. What happens if you just lower a little, like 100 Mhz. And 270 is not too high for an A64, I run mine at 8x300 with memory set to 133 (2400 Mhz CPU with 200 MHz memory).
 
Originally posted by: Concillian

I don't understand, you can get 200 MHz with the CPU frequency lower? That doesn't make sense. The two should be unrealated. What happens if you just lower a little, like 100 Mhz. And 270 is not too high for an A64, I run mine at 8x300 with memory set to 133 (2400 Mhz CPU with 200 MHz memory).
Click to expand...

no thats (100, 133, 166) not cpu frequency. that is the clock limit of the memory set in the BIOS of MSI Neo boards.


and 270MHz is certainly not too high. I think he can get to your first suggestion of a 133mHz memory clock which would as you said be almost DDR366 with a 35% FSB overclock.

133MHz +35%= 180MHz or DDR360
 
Right which I believe translates to 2:1 / 3:2 / 6:5 in terms of cpu to ram dividers.....

At 270 you can run at 4x HTT but likely 3x is better. Run the 133mhz option so that at 270 you would be running actually 180x2 (for ddr double pump) or 360mhz (near PC3000 levels)....

Try to run conservative cas timings at first to rule out memory in the overall ocing process...
 
Originally posted by: gururu
Originally posted by: Concillian

I don't understand, you can get 200 MHz with the CPU frequency lower? That doesn't make sense. The two should be unrealated. What happens if you just lower a little, like 100 Mhz. And 270 is not too high for an A64, I run mine at 8x300 with memory set to 133 (2400 Mhz CPU with 200 MHz memory).
Click to expand...

no thats (100, 133, 166) not cpu frequency. that is the clock limit of the memory set in the BIOS of MSI Neo boards.
Click to expand...

I was talking about where he says:
Originally posted by: Gumby84
Should I just lower the cpu freq and run the ram faster?
Click to expand...

This implies that he can run higher memory speed at lower CPU frequency. This is what doesn't make sense to me, and what my comment was pointed towards.


He is still light on the details. We don't know if he's tried any in-between settings (I'm assuming yes, and they don't work) or what latencies he's trying. We also don't know the RAM config (2x512?, 2x256?, 4x512? 4x256? 2x 1GB?) These are all potential factors, as the A64 platform in general is a little finicky with RAM, especially 3ith 3 or more "sides" per channel.
 
Yeah...I tired 133 in the bios and it won't boot, but if I drop the cpu down to like...2.1ghz I can run 166 and 200. Btw...It's Hynix pc3200 256x2 dual channel.
 
increase the voltage to the ram --- my d43's hynix's do 250mhz + at 2.7v and relaxed timings
at stock 2.5v though they wont go past 210mhz

 
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