real-world advantage of faster memory

Tabzilla · Sep 21, 2004

I recently bought a new a64 system to replace my p4 2.0a system, and i'm using 3 sticks of 256mb pc2100. I have overclocked my 2800+ to 2.4, which seems to be the cpu limitation and not that of the ram. My question is: how much of an improvement will i see (assuming all other speeds are the same) going from 133mhz to 200mhz? I realize the bandwidth is higher and all that, but I'm a gamer and i don't care about number, just FPS

Brandon

Tabzilla · Sep 22, 2004

oh come on, i'm sure someone here knows...

edwardaune · Sep 22, 2004

Well, everything pretty much work in conjunction with one another on a computer. So you should see an increase in frame rate because you are lessening, may not be much, a bottleneck possible prohibiting you from getting a few more FPS. You may want to think about upgrading ram pc3200 or 3500 and is your 2800 unlocked because if it isnt you got a pretty good speed with it. Definatley think about upgrading ram.

and btw WELCOME TO THE FORUMS

Shade00 · Sep 22, 2004

Real world performance? Probably very little difference. What timings are you running your memory at? Also, is your system running at 267x9 for 2.4ghz? If so, and if your RAM is still running with the 133mhz divider, then it's actually running at 184mhz. If you can keep decent timings at that speed, then I would say it's not really worth it to spend anymore money on RAM.

Albuquerque · Sep 22, 2004

Tabzilla said:
I recently bought a new a64 system to replace my p4 2.0a system, and i'm using 3 sticks of 256mb pc2100. I have overclocked my 2800+ to 2.4, which seems to be the cpu limitation and not that of the ram. My question is: how much of an improvement will i see (assuming all other speeds are the same) going from 133mhz to 200mhz? I realize the bandwidth is higher and all that, but I'm a gamer and i don't care about number, just FPS

Brandon

This isn't hard to figure out... Your CPU cannot hold all the game's AI and physics data in it's cache; it must use your system ram to continually update this information as the game runs. If your CPU is doing 2.4ghz and your ram is running at a measly 133mhz, where do you honestly think the bottleneck lies?

It would be like putting an 800 horsepower motor in your car, but feeding it with a one gallon-per-hour fuel pump. The motor will have no problems idling, but you'll NEVER get performance out of it when you cant send the necessary fuel.

There's no magic formula to tell you how many more FPS you'll get; a 50% increase in memory bandwidth does not correlate to a 50% increase in all framerates. Some games will get big gains (anything that has an engine created by iD), some games will get moderate gains (anything Unreal engined) and some games may never notice (a lot of RTS's).

It's quite likely that your load times will go slightly quicker, your boot times will get slightly shorter, and your overclocking options will become better. But there is no solid "performance increase number" to go by.

edwardaune · Sep 22, 2004

Albuquerque said:
This isn't hard to figure out... Your CPU cannot hold all the game's AI and physics data in it's cache; it must use your system ram to continually update this information as the game runs. If your CPU is doing 2.4ghz and your ram is running at a measly 133mhz, where do you honestly think the bottleneck lies?

It would be like putting an 800 horsepower motor in your car, but feeding it with a one gallon-per-hour fuel pump. The motor will have no problems idling, but you'll NEVER get performance out of it when you cant send the necessary fuel.

There's no magic formula to tell you how many more FPS you'll get; a 50% increase in memory bandwidth does not correlate to a 50% increase in all framerates. Some games will get big gains (anything that has an engine created by iD), some games will get moderate gains (anything Unreal engined) and some games may never notice (a lot of RTS's).

It's quite likely that your load times will go slightly quicker, your boot times will get slightly shorter, and your overclocking options will become better. But there is no solid "performance increase number" to go by.

Yea what he said. And I still think an upgrade in ram would highly benefit. What can I say Im hard headed. If you want to most out of your system, put the most you can into it, that way you dont have excuses.

Shade00 · Sep 22, 2004

Guys, memory latency is a lot more important than pure bandwidth for the A64. An A64 with 200mhz RAM @ 2-2-2-5 will run faster than an A64 of the same speed with 230mhz or 240mhz RAM @ 3-3-3-8 or 3-4-4-9. Sandra will tell you that you have more bandwidth, but in-game FPS will show the true difference.

dukat · Sep 22, 2004

i see a nice boost in 3D01 when going from 200mhz to 220mhz fsb (same timings), but not a single fps difference in d3 timedemo.
system in sig.
would be interested if others have experienced the same

Albuquerque · Sep 22, 2004

A 10% speed increase (200 -> 220) at the same timings isn't going to net you much. It may not even be noticeable. If you are forced to use lower timings at the higher speed, you may even get less performance.

However, a 50% speed increase (133 -> 200) at the same timings is going to be VERY NOTICABLE. If you buy higher quality ram and can get tighter timings, it will be even more noticable.

It's true that AMD processors love tight timings, but there's quite a difference when talking about a 10% increase in mhz versus a 50% increase.

Shade00 · Sep 22, 2004

Albuquerque said:
A 10% speed increase (200 -> 220) at the same timings isn't going to net you much. It may not even be noticeable. If you are forced to use lower timings at the higher speed, you may even get less performance.

However, a 50% speed increase (133 -> 200) at the same timings is going to be VERY NOTICABLE. If you buy higher quality ram and can get tighter timings, it will be even more noticable.

It's true that AMD processors love tight timings, but there's quite a difference when talking about a 10% increase in mhz versus a 50% increase.

With A64s, it's not as simple as going from 133mhz to 200mhz.

If he's running 2.4ghz with a 2800+, then he's likely running 267x9. If he's running the 133mhz divider right now, his RAM is at 185mhz. If he were using the 200mhz RAM divider, his RAM would be at 267, which is not going to happen without some excellent RAM.

So, if his RAM is running 185mhz at good timings, the next step is the 166mhz RAM divider, which would put him at 218mhz. Now, if he finds RAM that can do equal or better timings than what he's running now, then he will see a performance increase. However, if he's able to run 2-2-2-6 now and has to run 3-3-3-8 or 3-4-4-9 at 218mhz, then he'll see no improvement in performance. Latency really does make a very big difference on the A64; much more so than the P4 or AXP.

Tabzilla, can you tell us what speed your RAM is at now? Running CPU-Z is an easy way to tell the speed and the timings.

I believe the biggest performance gain would be netted by going to 1gb of RAM. There's a noticeable difference, even over 768mb.

dukat · Sep 22, 2004

yeah, you are right, 133-> will be a noticeable inrease.
my post was more related to those people who squeze out the last from their nf2 boards (cant speak for other platforms), put alot of efford and money in it for a VERY small real world advantage.

Tabzilla · Sep 22, 2004

yes, i am running at 269x9, but i clocked my memory at 100mhz in the bios (apparently that's called a "ram divider"), so my corresponding memory frequency is 134.7mhz. my timings are 2.5-3-3-10.

AnomalyX · Sep 22, 2004

I noticed only a slight improvement in Sandra from 5-4-4-2 to 7-3-3-2. Example: 73% efficency to 74% / 5520/5587 -> 5587/5602. I haven't really benchmarked games yet, just visually, to try to see any changes. I don't feel like running 3DMark03 right now, but I do remember that I got a good jump from
the 1st timing to the next. Maybe about 100 pnts., from what I can remember.
Making your memory as efficent as possible never hurts. We all know that when overclocking, everything is stressed as it is, so if you can make any part of your system more efficient, then do so. You don't want any bottle necks.

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