Need help with timings for PC4000 RAM!

[8bit]

Hey all,

I bought some PC4000 RAM (www.aria.co.uk Aria's own brand, the ones with heatspreaders) recently to go in my Athlon XP 2200 machine (133MHz DDR FSB). Yes I know it's way over spec'd for the machine but I'm planning an Athlon64 Socket 939 upgrade after Xmas and needed to up from 512Mb to 1024 at the time so one less thing to buy along with chip, mobo etc. next year...

The Arianet RAM came with no info on timings or anything like that whatsoever and I'd like to be able to push the timings etc. to some optimum point on my current system. I can o/c the FSB in my BIOS already (nowhere near the 1GHz the RAM is rated for) and get some extra memory bandwidth that way but would like to tweak the timings cos I don't get out much and that sort of thing gives me a strange sense of satisfaction.

Basically is there a rule-of-thumb with the different classifications of RAM or even a chart I can follow? I'm happy with overclocking and stuff besides RAM, it's always mystified me a bit...

[skattrd]

Afaik theres no "rule-of-thumb" or anything like that with RAM timings its like most overclocking, a case of trial and error to see the best/tightest timings you can get stable.

5,2,2,2 is the lowest/tightest timings possible and the domain of bh-5, OCZ EB etc.
I severly doubt you'll get generic pc4000 anywhere near that as its designed for high fsb not low latencies - the best I've got out of my Geil is 7,3,3,2.5

[Firelord]

pc4000 is usually as in 9/10 3-8-3-3. Thats some slack timings for AXP

The reason they get it to 4000 specs is cos they relax the timings which is fine in Intel but sucks in AXP machines.

Only way of getting 250FSB 2-5-2-2 is some BH-5/TCCD and about 3.3/3.4v to the RAM.

[SilentDeath]

TCCD? what rams that?

Start with what ever the defualt is, at the speed your running it at, use memtest86 to test it, and put it as low as you can more voltage always helps too

[BUFF]

TCCD?

Samsung modules.

[8bit]

ok ok, thanks so far but still a bit in the dark. what do numbers like 5,2,2,2 mean? I found the timings stuff in my BIOS and I presume the numbers are quoted in a specific order but what do each of the digits in 5,2,2,2 or 3-8-3-3 actually correspond to?

thx again,
8bit

[Rave]

What motherboard mate?

Rich :¬)

[8bit]

Gigabyte GA-7DX at the moment, intending on Asus A8V Deluxe WiFi for A64 upgrade imminent... That runs mem up to 800MHz, got the PC4000 so I could push it a bit...

In fact, the Gigabyte mobo does auto timing detection, is it likely to pick sensible values or should I fiddle?

8

[Kumagoro]

Latency really doesnt make that much difference. Even so, as you will be running the ram a lot lower then its rated freqs you should be able to use a lower latency setting.

[Firelord]

Latency really doesnt make that much difference. Even so, as you will be running the ram a lot lower then its rated freqs you should be able to use a lower latency setting.

Latency does make a difference otherwise we wouldn't have the option to change em in the bios

[Kumagoro]

The higher the freq the less effect latency has.

[SilentDeath]

It makes more than a noticable difference in benchmark scores, whether it would be noticed in real games I dont care.. but there is a difference.

Latency i show many clock cycles the ram idles between doing stuff. With higher speed ram, each cycle counts for less, in effect giving lower latency in that way. The option in the bios is to set how long it waits for.

On most mobos they are listed in the order of least effect-> most effect. On my nf7-s anyway.
Once you have your ram you should chose the speed that you want to run it at, based on cpu and mobo overclocking, and then adjust the ram voltage to give a bit more option on the latencys. Use memtest86 or one of the many other apps to test the mem after to check thats stable, and make sure it doesnt get too hot (I.E you can still touch it without burns )


Most memory will go a lot past its rated speed with a bit more voltage

Samsung modules.

Ahh, I would have guessed
Samsung stuff does o/c really well. I had two sticks of pc2700 (166) which I achived 225mhz (450ddr) speed on @ rated timings @ 2.8v.
How good is TCCD compared to BH-5? And how much it cost/from where?

[Kumagoro]

Every arcticle, magazine i have read shows the difference to be only a couple of % is the amount of money spent for low latency ram worth it, i think not.

Better to spend the money on cpu or ram or beer.

If you have money to burn then its fine why not get the best, but how many people do.

In the latest PC extreme which should be out by now i think they do a ram test and find only a couple of % diff at best even when they went up to CL 6.