Memory Speeds and Latencies

[Thermopylae_480]

Which is better if your not doing very large overclocks? To have your memory at a higher frequencies and higher latencies or lower frequencies with lower latency?

Current Frequencies and Latencies
Frequency - 271.7 MHz clocks
FSB: DRAM Ratio - 3:4 clocks
CAS# latency - 4 clocks
RAS# to CAS# Delay - 4 clocks
RAS# Precharge - 4 clocks
Cycle Time (Tras) - 11 clocks

[zAAm]

Are your RAM running at 271MHz Thermopylae, or is you FSB 271MHz? Because that would make your RAM at something like 205MHz which isn't overclock at all. ;) And frequency is better if you overclock more than about 10% I'd say compared to tight timings and stock frequencies.

[Thermopylae_480]

Memory is running at 542MHz. Its not really overclocked the RAM is just a little fast. I guess I should read up on RAM; I just don't know enough about it.

[Poisonsnak]

Hmm I'm on an athlon64 so no ddr2 experience here but wow CAS 4 seems really really long to me I never go above 2.5 but maybe that's a DDR2 thing.

I got the same bandwidth with 250MHz memclock (500MHz "data rate") with 2.5-3-3-6 timings as 275MHz (550 data rate) with 2.5-4-4-8 timings, so I would say go for tight timings at low frequencies. If you get memtest86+ (www.memtest.org) you can get an idea of your mem bandwidth without having to boot into windows, the tweaking goes much faster that way.

[Thermopylae_480]

You can get DDR2 533 with 3-3-3-9, but mine is to old and I can't get the timings any lower because the RAM is cheap. So I just opted to keep the 4-4-4-11 and overclock it. I imagine if I underclocked the RAM I could tighten up my timings. My motherboard doesn't have that great OC settings for RAM I can change timings all I want but I only have an option of 400Mhz 533Mhz or 600Mhz. So would it be better to tighten the timings and go down to 400Mhz or go to 600Mhz and keep my timings at their current setting? In addition what is SPD as it pertains to memory.

[Bob111]

I have read alot of reviews on intel systems and ddr2 and as far as fps on games these folks seem to believe that a higher frequency pays off better as opposed to lower timmings. I have an Intel system and when running real time games with fraps running, I get an increase in fps when I overclock the memory by raising the fsb by at least 20%

[Thermopylae_480]

Thats interesting. I would have thought that memory running at 533MHz with a latency of 3 would allow more instructions per second than 600MHz with a latency of 4. Can't 533MHz with a latency of 3 process ~177,666,666 instructions per second? While 600MHz with a latency of 4 process ~150,000,000 instructions per second. I know instructions and processing is probably not the right terms, but Its all I could think of. Doesn't a latency of 3 mean it takes 3 clock cycles to process one segement of information?

[Bob111]

I'm by far not an expert on memory timmings and frequencies . But from what I have read, Amd's memory controller is alot more efficient than Intel's. When I run synthectic benchmarks on my different memory settings you are correct in that the results do come out a bit higher on these test but on my system do not improve on in game fps as one would imagine but if I were to loosen up the timmings and increase the freq. from 533 mhz to 667mhz or 712 mhz, I can show an improvement of 5 to 15 fps on games.

[Thermopylae_480]

Interesting. I'll have to try it out.:)