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RAM Ratios...what do they mean?

M

mitchafi

Golden Member
Ok so I have the system in my rig running at 219 FSB....CPU-Z tells my my ram ratio is CPU/10. Before I began increasing the FSB it told me I had 1:1. Can anyone briefly explain to me what this means and the effects it will have on performance?
 
First, I think it's cool that K8 boards have this now. Previously only P4s had it.

Memory ratios control the FSB to Memory Speed ratio. For example if your A64 FSB was set to 200Mhz and the ratio was 1:1 then the memory would also run at 200Mhz. Likewise in a P4 environment if the FSB was set to 250Mhz and the ratio was 5/4 then the memory would once again run at 200Mhz. Most people (on A64s anyway) try to hold 1:1 as it offers the best performance and A64s don't OC high enough to change it assuming you have good memory which you do. If you also look that Mushkin memory is rated at about 220Mhz you can keep the ratio 1:1 if you even get that high on the FSB.
 
So since I have a ratio of CPU/10 instead of 1:1 should I lower my FSB back closer to stock until my ratio goes back to 1:1?
 
Originally posted by: mitchafi
So since I have a ratio of CPU/10 instead of 1:1 should I lower my FSB back closer to stock until my ratio goes back to 1:1?
Click to expand...

No, you control the ratio independantly of the FSB and memory speeds. So as long as your FSB is under 220Mhz you could change the ratio to 1:1 and your memory would work in sync (best for Athlons) with the FSB.
 
Originally posted by: PorBleemo
Originally posted by: mitchafi
So since I have a ratio of CPU/10 instead of 1:1 should I lower my FSB back closer to stock until my ratio goes back to 1:1?
Click to expand...

No, you control the ratio independantly of the FSB and memory speeds. So as long as your FSB is under 220Mhz you could change the ratio to 1:1 and your memory would work in sync (best for Athlons) with the FSB.
Click to expand...
It's a A64...this is where not having to access RAm via FSB comes in.
Asynch shouldn't matter. CPU/10 = 200MHz (PC3200). 1:1 = 2000MHz. When you can find some PC32000, call me 🙂.
 
So how do I change the ratio to 1:1? And the ram is PC3500 so wouldn't that mean it would be able to clock a little bit higher?
 
Originally posted by: PorBleemo
First, I think it's cool that K8 boards have this now. Previously only P4s had it.

Memory ratios control the FSB to Memory Speed ratio. For example if your A64 FSB was set to 200Mhz and the ratio was 1:1 then the memory would also run at 200Mhz. Likewise in a P4 environment if the FSB was set to 250Mhz and the ratio was 5/4 then the memory would once again run at 200Mhz. Most people (on A64s anyway) try to hold 1:1 as it offers the best performance and A64s don't OC high enough to change it assuming you have good memory which you do. If you also look that Mushkin memory is rated at about 220Mhz you can keep the ratio 1:1 if you even get that high on the FSB.
Click to expand...

Ok you lost me...😕
 
Originally posted by: mitchafi
So how do I change the ratio to 1:1? And the ram is PC3500 so wouldn't that mean it would be able to clock a little bit higher?
Click to expand...
Look in the BIOS. My experiences w/ K8s so far has been Tyan K8Ws 🙂
 
I don;t think it has the dividers. You are running 219 x 4HTT = 876 x 2 = 1752 total HTT effective. You CPU is running 219x10=2190 mhz. I decent OC. All is fine. How do you like the setup ?
 
It's nice...3DMark03 crashed on 220...any point trying again? Im getting ready to start OCing my 9800 Pro but I have a quick question you may be able to answer. Should I overclock my memory clock speed and core clock speed at the same time or overclock core speed as far as I can and then memory clock speed as far as I can?
 
Sounds like yours is like mine. Run it at 218 since 220 crashed. As for the ATI 9800, use ATI tool. It will auto-find your best clock. Try core fire, then artifacts, then memory, then artifacts again. Takes a while.
 
So the first question was never actually resolved...is a ram ratio of cpu/10 inhibiting my performance on an A64 (see sig)
 
I thought I answered your question. A 3000+ and a 3200+ run at 10x the 200 memory speed, and ALLWAYS at 1:1. The 3400 runs at 11x memory. The FX53 runs at 12x memory (or more, since it runs PC333 sometimes ??)
 
Originally posted by: mitchafi
So the first question was never actually resolved...is a ram ratio of cpu/10 inhibiting my performance on an A64 (see sig)
Click to expand...

OK, the RAM speed of CPU/10 does not mean that it's CPU host (200) / 10, its CPU core clock that is 10 times faster than your RAM. thus, it should not affect you negatively.
 
Originally posted by: Markfw900
I thought I answered your question. A 3000+ and a 3200+ run at 10x the 200 memory speed, and ALLWAYS at 1:1. The 3400 runs at 11x memory. The FX53 runs at 12x memory (or more, since it runs PC333 sometimes ??)
Click to expand...
No, it runs at 10x, 11x and 12x of 200MHz 🙂, which is also used to get the HT-link frequency, and the memory is either some ratio of that or the CPU speed. Oddly enough, CPU/10 sounds right--Tyan's K8W happens to use that as a way to do it (so anything other than PC1600 and PC3200 run slow).

In short, no. Hopefully this can clear things up:
200MHz*4 = 800MHz HT^ * 2 (two links) = 1600MHz.
200MHz * 10 = 2GHz CPU / 10 = 200MHz * 2 (the 1st D in DDR) = 400MHz RAM (PC3200).

218MHz * 4 = 872MHz HT * 2 (two links) = 1744MHz.
218MHz * 10 = 2.18GHz CPU / 10 = 218MHz * 2 = 436MHz RAM (PC3500).

^ - I know HT has some DDR and crap, so that's marketting MHz, just so I don't have to look it up.
 
Thank you once and for all. When I ran CPU-Z at stock speeds it said 1:1 and when I ran it at 219 it said CPU/10. That is what was causing the confusion. Fortunately, all you smart people have taken your time to clear it up for me 🙂
 
Originally posted by: PorBleemo
Originally posted by: mitchafi
So since I have a ratio of CPU/10 instead of 1:1 should I lower my FSB back closer to stock until my ratio goes back to 1:1?
Click to expand...

No, you control the ratio independantly of the FSB and memory speeds. So as long as your FSB is under 220Mhz you could change the ratio to 1:1 and your memory would work in sync (best for Athlons) with the FSB.
Click to expand...

Sorry to bring this thread back from the dead but I was reviewing it out of boredom and seemed to have overlooked this reply. Would you mind telling me how to change the ratio independently (i.e. not the whole FSB). Is that under RAM voltage in bios? Right now I have it set on automatic.
 
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