OCZ PC2-6400C4 Reaper HPC overclocking

Berserker · 16 Nov 2008 at 18:10

Can anyone give me some rough ideas of what's achievable overclock wise with this RAM (on stock volts). I've just installed some of this and want to give it the proverbial boot up the backside, but at the same time I don't want to push my luck as about the only testing option I have right now is Memtest86.

PS - it's currently surviving Memtest at 480MHz (DDR960) 5-5-5-18, but reading others sigs I suspect I'm pushing my luck there and wouldn't be surprised if I saw an error soonish.

PPS - It's definitely Reaper HPC, not ReaperX.

Update - 1:12 clock, 1 Pass, 53% through the next, no errors.

Rroff · 16 Nov 2008 at 21:48

Mine* would do upto 960MHz on 4-3-3-7 timings with stock voltage - but I'd get the odd random error that seemed to be memory related even tho it passed memtest and a few hours of prime fine. 950MHz seemed ok tho.

Coupled with an nForce 650 board and a fast CPU I was getting almost 12Gig/s in everest read test off them.

*I have the 2gig kit - the 4gig version isn't so good for overclocking timings wise.

Berserker · 16 Nov 2008 at 22:41

I'm very much a noob at this, and I still favour long-term stability over speed. That's why I only pushed the E6600 in this system as far as 320x9. I was using 320x2.5 (i.e. stock) with the GeIL RAM I had in before, but since swapping that out for OCZ yesterday I thought I'd give 320x3 a go on slack timings (which I assume will be better all-round than 320x2.5 on tighter timings).

If there's even likely to be a hint of instability I'd rather back off, but since I don't know what I'm doing I'd rather have input from people who do - otherwise I'll just back off to stock.

PS - relevant bits from rest of system. Gigabyte GA-965P-DS3, E6600, Freezer 7 Pro, CM Stacker.

Reality|Bites · 17 Nov 2008 at 15:04

2.5? 3? I take this is your CAS latency and not your CPU multiplier.

Rroff · 17 Nov 2008 at 15:44

I think hes talking about FSB to memory bus multiplier - theres no way you'd get CAS2.5 on DDR2 under normal circumstances at 800+MHz.

Berserker · 17 Nov 2008 at 16:10

I am talking about the multiplier. I just don't know the technical terms. I R noob, remember.

Currently CPU is on 9x320 = 2.88GHz
RAM is on 3x320 = DDR960 (480MHz) CAS5 (5-5-5-18).

Previously I had the CPU on 9x320 and RAM on 2.5x320 = 800 (stock PC6400). The GeIL memory I had in previously was just the cheapest I could find at the time (memory prices have dropped like a stone since), and it wasn't so keen on overclocking as this stuff seems to be.

Just so you know, I chose 5-5-5-18 for no other reason than because that's what the SPD seems to be (yes, I know they can do 4-4-4-15, or better, but I do know enough that slackening the timings a little helps when overclocking).

And as for the Memtest, Clock time 20 hours, 24 passes, no errors. :cool:

Rroff · 17 Nov 2008 at 16:40

300% Memtest (which should take under an hour for 2gig) is generally enough to detect 99% of memory problems.

Berserker · 17 Nov 2008 at 19:08

300%? Do you mean 3 passes?

In any event, I think I'm set. My only concern, given that I am a noob to this, is the usual one - am I likely to break something (over the long term)? I suspect not, but I still worry about this sort of thing.

Other than that, I'm happy with my 20% performance gain.

Berserker · 18 Nov 2008 at 00:42

I reckon it'll probably do...