Low latency memory vs. faster memory?

jpinard

I have to decide between these 2 specs.... which will give me better GAME performance?

This will be running in dual-channel mode with two 1 Gig memory modules (2 Gig total).

* PC 3500 (433MHz) at CL3-3-3-8

vs.

* PC 3200 (400MHz) at CL2-3-2-5

Right now I run 1 Gig (2x512) PC3500 slightly overclocked (+4 MHz).

Thanks!

If I get the low latency 400 MHz memory the bus will be set at 400 MHz. If I get the higher latency memory, I will probably run the bus at about 405 MHz.
Thank you!

----------------------
My current specs:

* OS: Win XP Home SP2
* Directx 9.0c
* Processor: AMD FX-53
* Motherboard: Asus A8V Deluxe rev1.2
* Bios Rev: Version 1007
* VIA 4-in-1 Version 4.51
* VIA SATA Raid version 2.20D
* Memory: 1 Gig Kingston 3500 (433MHz)
* Video Card: ATI Radeon X800 XT Platinum Cat 4.9
* Sound Card: SB Audigy 2 ZS (latest non-beta drivers)
* Pioneer DVD-RW Drive
* Samsung SATA 120 Gig, 7200 rpm, (Model ST316002 3AS - Drive C)
* Seagate SATA 160 Gig, 7200 rpm, (Model ST3160023A - Drive D)
* Seagate ATA-133 160 Gig, 7200 rpm, (Model ST3160023A - Drive E)
* Logitech MX510 Gaming Mouse
* Sound settings utilizing 5.1 speakers and EAX 3
* Klipsch ProMedia 5.1 Surround System
* Mitsubishi Diamond Pro 2060u - 22”

CDsDontBurn

Athlon 64s prefer lower latency memory modules over having faster memory, whereas p4s prefer to have a faster bus than lower latencies.. If you can get yourself a hold of some DDR500 that can do 2.5-3-3-7 would be best because then you can run the memory at like DDR433 at 2-2-2-5 timings. G.skill, and Corsair XMS LL series, and some of the newer revisions of OCZ are the only three i know that can perform that well. I'm sure that there are other brands out there that can perform very well also.

The_Neon_Cowboy

I'd say * PC 3200 (400MHz) at CL2-3-2-5 probubly but i'd look for 2-2-2-5!
It would be a good idea to take a look @ www.newegg.com

jpinard

Thsnks for the replies, but the porblme here is getting a matched set of TWO 1 Gig modules. There are very few 2 Gig (2x1) options out there. In fact, for dual channel what I listed are the only two real options on the market...

CDsDontBurn

another thing. If you want the best performance out of your machine, you will want to get four 512Mb modules. Running 512Mb modules will allow you to get even lower latency timings than running two 1Gb modules.

nuG

good point. i concur.

jpinard

I thought the more modules you have, the higher latencies you have to run, since it's more difficult to coordinate data across 4 modules vs. 2?

CDsDontBurn

yes, this is also true, but the reason for this happening is only because there isn't as much voltage going to each stick of ram in the system. Each stick of ram needs to have its voltage fed to it, and w/more sticks of ram present, the same amount of voltage needs to get fed to more sticks of ram. However, the reason why 1Gb modules have high latencies is because the information accessed has to be cycled through an entire 1Gb module making it perform slower (i.e. higher latencies). Where as when using 4x 512Mb modules, the information being accessed only needs to travel through 1x 512Mb stick of ram at a time.

So say for example that the information being seeked is on the second half of one of the 512Mb sticks, then it only needs to look no further than 512Mb. Now, if the same information were being seeked on a 1Gb module, and the information were also on the second half of the module, the information being accessed won't be accessed until the accessing has come towards the end of the 1Gb module (kinda confusing i know, but that's how i can explain it best).

The_Neon_Cowboy

your better off getting 1gb unless here is some specail reson you needing more and it won't help gameing 0% can even hurt your bechmark scores but you'll be able to have more applications open at one time. Unless your video editing or something 2gb is over kill

CDsDontBurn

Having 2Gb does help out when you play games. The differences i've noticed on machines similar to mine but have 2Gb of RAM vs. my 1Gb is that when playing games (especially alot of the newer games), the games do not lag at all. They play like silk. From what i've heard, EQ II is one game that would definately benefit from having 2Gb of ram amoung other things *cough* 512Mb video card *cough*.

jpinard

So, if I up the voltage, then 2 more sticks of 512 would be better? On the AMD 64 processing site they keep saying you have to go to a 2T command rate when you use 4 sticks vs. 2... And this makes a pretty sizable dent in your performance... Is this true? And can it be different between Ahtlon 64 (FX-53) vs. Intel platforms?

CDsDontBurn

Well, if you're running 4 sticks of ram, your default timings will probably loosen up a little bit (say from 2-3-3-6 to 2.5-3-3-7) when running 4 sticks of ram at stock voltages and stock speeds. So getting 4 sticks of ram will make it a bit more difficult to OC the ram. As far as the ram going from 1T to 2T command, that i am not sure about. But i do not see why it would default to the 2T command when going with 4 sticks of ram.

jpinard

cool, thanks!

Zardon

Im not quite sure were cdsdontburn got his information but ive always found two sticks compared to four better for latencies. Personally id go with the two 1 gig sticks rather than the four 512. Interleaving between 4 modules on a mobo means 1T is rarely an option.

CDsDontBurn

yea yea......np man .......that's what we do here......help each other out .

gyoung

Before deciding to purchase 4 vs 2 sticks of ram, make sure you read your Mother board manual to see what that will do to your timings. It will also affect your ability to overclock.

itchy5

id go with fast ram and just set it at ddr400 with LL if i have to. most fast ram does Low Latency @ ddr400 any way OCZ and Corsair are my perfered memory <3 OCZ VX

C47

HEY what about amd athlon xps

CDsDontBurn

well, that depends on the chip you have. If yours has the unlocked multiplier then, you can adjust both the multiplier and the FSB, giving you alot more overclocking options. Athlon XPs generally prefer a larger FSB over a higher multiplier.

Example: a barton 2500xp has a stock speed of 11x166 = 1.83Ghz. Now, if you increase the FSB to 200 (11x200) you'll end up with almost a 400Mhz OC (2.2Ghz = xp3200 specs). Now, if the xp2500 has an unlocked multiplier (good luck finding one cuz they're hard as hell to find now, unless you already have one), you can change the multiplier to say 10x220FSB which will get you the same 2.2Ghz core clock (xp3200 specs again), but you have effectivley increased your FSB, giving you better performance out of your chip.

Somnambulator

thats absolutely correct. the Integrated Memory Controller of Winchesters does not support 4 DIMMS @ DDR400 CPC 1T. you can only run 4 DIMMS at DDR333 (pc2700) at 2T, which will cripple not only your RAM, but your CPU as well.

btw, pc3500 is 217mhz FSB = 433mhz RAM. if you want the pc3500 chips, it would be absolutely pointless to buy them to run at *only* 200 or 205 mhz since most likely they wont hit the same low timings of the pc3200 sticks you listed.

also, if you arent plannin gon doing some extensive tweaking/OCing, lower latencies arent that big of a deal. pc3200 cas2-2-2-5 (or 2-2-2-10 if NF4) offers only roughly 3-6% better total system performance compared to cas2.5-3-3-10. if you just want to build a PC with very little to no plans on doing some hardcore overclocking, then "value" pc3200 RAM will save you considerable money (or let you get more of it) with minimal performance hits.

low latencies are usually tauted for a few reasons:

1 - Athlon XP systems CRAVE low timings. 230 @ 2-3-3-11 will crush the performance of an AXP running 260 @ 2.5-3-3-11. - A64's, however, want higher FSB. they are in-between AXPs (low latencies) and P4s (outrageous clock speeds). Yes, an A64 running 10x275 with "loose" timings of 2.5-3-3-10 or 2.5-4-3-10 will DESTROY an A64 running 10x230 2-3-3-10, probably even up to 240mhz. sure, memory bandwidth will be relatively the same (or higher for the lower clocks/ latencies) but overall performance will be lower.

2 - low latencies generally give you more headroom when overclocking the RAM. sticks rated for 2-3-2-5 obviously have more room to raise timings (which lets you raise clockspeeds higher) than sticks rated at 2.5-3-3-7.

for "normal" (read: non-OC/tweaking) systems, however, unless you can justify spending the extra $50-100, theres no reason to go with Cas2 pc3200 sticks over cas2.5 pc3200 sticks. you'll get better performance with lower latency chips (better ram) but the difference is generally negligible -1 maybe 2 FPS in Source or D3 if you're lucky (and a gamer)

jpinard

Excellent, thanks SOmnan - you really brought things into focus.

jpinard

Ok, I got my new memory and it's failing Prime95 It's settings are 2-3-2-5 ... exactly what do those numbers correspond to in the BIOS? ex. trcd, tras, trp etc etc.

It's this memory:[color=darkred] [/color][color=darkred]http://www.pdpsys.com/products/PDC2G3200LLK.pdf[/color]
Thanks for the help

Somnambulator