2-3-3-6 PC3200 or 3-4-3-8 PC4000

[fish99]

Hi, buying new ram on wednesday, 2 GB dual channel kit for a 939 board. Just wondering what anyone thinks would be quicker, 2-3-3-6 PC3200 @ 207 MHz or 3-4-3-8 PC4000 @ 250 MHz?

My A64 4000+ is running at 3 GHz / 250 Mhz FSB, so the PC4000 will run at 250 Mhz. The PC3200 would be running on a divider at 207 Mhz.

So, 43 Mhz extra speed from the PC4000, or the quicker timings of the PC3200? The makes in question are Corsair PC3200 and OCZ PC4000.

Thanks a million
Simon.

 

[fish99]

Just a quick addition - I can now confirm the chip hits 250 Mhz FSB without problem.

So it's 2-3-3-6 at 207 MHz PC3200 versus 3-4-3-8 at 250 MHz PC4000.

Quicker timings versus quicker clock speed. Any ideas which would come out on top?

 

[fish99]

Do you remember it as being a significant difference or was it quite close?

Cheers

 

[fish99]

The higher speed should be better, had my OCZ VX at 275MHz 2-2-2-5 3.3V if you really like low latencies and high speed Its at 250MHZ 2 2 2 5 2.85v now

Just been looking for PC4000 that can do those sort of timings and not finding anything that's currently available. Is it rated 2-2-2-5 or is that tweaked timings? I probably can't afford anything like that, looking at around £150 or less.

 

[fish99]

Would a measurement of memory bandwidth take into account the timings? I mean obviously memory running 50 Hz faster there's going to be more bandwidth there, but does a measurement of bandwidth alone give you the whole picture, ie that the complete system is quicker? Does it take into account the higher latency?

If it does then Cob has given me the answer as to which is going to be quicker and I should go with the PC4000. I did read on Anandtech earlier that A64 doesn't need extra memory bandwidth and tighter timings are more important, as trojan698 said.

I got better results from running my OCZ PC4000 at 247@3-4-3-8 than 196@2-3-3-6. Both Everest and Sandra gave far better bandwidth scores for 247.

 

[fish99]

^ Actually, a point worth considering there. Do some benching to see what gives the better result, maybe a go between of tight timings and fastest speed you can manage.

Not able to do a direct comparison since my ram won't work at 250 MHz, but I was able to test the difference between 2.5/3/3/6 timings and 3/4/4/8 timings on my ram, and there really was very little difference. 1 fps in Doom 3, nothing in Fear, 169 pts in 3DMark03, 12 pts in 3DMark06, 1s in SuperPI 1M.

Also compared ram @ 166 with ram @ 207 (identical timings) to see what sort of difference extra bandwidth made, and while it was again very small, it was a bigger difference than the quick timings made - 4 fps in Doom 3, 1 fps in Fear, 329 pts in 3DMark03, 17 pts in 3DMark03 and 2s is SuperPI 1M.

I think you can extrapolate from those numbers that the difference between 250 and 207 MHz would be more than the difference between 2-3-3-6 and 3-4-3-8 timings, just about. Think I'll go with the PC4000 then.

 

[fish99]

<slaps forhead>

All of the above is irrelevant actually, since I didn't realize you can buy PC3200 that will hit 250 MHz.

Apparently G.Skill ZX does 2-3-2-5 @ 200 MHz and 3-4-4-8 @ 250 MHz (2.76V).

And OCZ EL Platinum does 2-3-2-5 @ 200 MHz and 2.5-3-3-7 @ 250 MHz (2.75V) which is even more impressive.

So I don't have to choose, I can buy the OCZ PC3200, test with quick timings at 200 MHz, test at slacker timings at 250 MHz and see which is quicker. Makes you wonder if PC3200 and PC4000 aren't just the same chips with different default timings.

Sorted

...pitty OcUK have sold out though... will have to buy elsewhere

 

[fish99]

Well I've got the new OCZ EL Platinum PC3200 and it won't do 250 MHz, not on my board anyway, not even at 3-4-4-8-2T 2.8V. Not willing to go over 2.8V because of the OCZ warranty.

Oh well, I bought it cause I needed 2 GB not because I needed it running 250 MHz, and it's only cost £10 more than the lower specced PC3200 I was looking at, and it does run very tight timings at 207 Mhz (2-3-2-5-1T), plus it looks very nice.

A little disapointed but I'll get over it

 

[fish99]

Cheers for the offer but the money is spent on the OCZ Platinum now. TBH if that review I read had the OCZ at 260MHz 2.5-3-3-7 (2.75V) and I can't get to 250 MHz at 3-4-4-8 (2.8V) then maybe my board isn't the best in the world for overclocking on.

I might have another play. The OCZ might not do 250 MHz but it probably will do more than 207 MHz and let me push the CPU FSB up a bit further.

 

[fish99]

Ok.

If I lower than CPU multiplier, does that let me test the memory seperate from the memory controller, or is the memory controller tied to the memory clock speed?

 

[fish99]

your pm is block so ill say it here just to ask>4 sticks!
you interested in 2gb ddr pc4000 vx runs at 2.2.2.6 3.3v what mobo dram voltage does it support

Fraid not sorry, already bought some OCZ. I could change ram and still have the same problem, afterall my OCZ may well do 250 MHz in another board or with another CPU.

More likely down to your board and the other ram settings such as strength and skew value

Don't know what those settings are but I'm guessing they're not something I can do anything about/change? TBH I'm pretty happy running quick timings and a divider. If the OCZ had worked at 250 MHz it would only have been 1 or 2 fps difference at most in most games.