Originally posted by: endergotgame
Thanks Bonzai! i was thinking should i just Take out the PNY and run the 2 gigs of dominator? Would this help the OC? and would it effect my gaming?
Check the "Memory and Storage" forum for the performance of PNY. I'm familiar with the manufacturer, but not with the quality of the product for more than running machines at stock settings.
The Dominators are Corsair. Wait a minute . . . .
[Checked Newegg on these]. Yeah -- I'd go with Corsair just on general performance reputation.
First, let's talk about the size of the modules. I think these Dominators were a more expensive model, and for good reason. The DDR2-800's were spec'd to run at latencies of 3-4-3-9. Corsair had been a vanguard for low-latency DDR2 RAM, and these fit the spec of those that first appeared and then disappeared as people gobbled them up.
If you are running Windows XP 32-bit, I'd stick with 2GB or 2x1GB kits. If you are running VISTA 64, then I'd recommend 2x2GB or 4GB of RAM. As I said, you could look into the 780i forums to see if there are limitations to running two of these kits, but I've found 4GB to be more than adequate, and a good trade-off against power-consumption and OC'ability.
You can, at the moment, get a 4GB-kit of those dominators for an after-rebate price of $70:
Dominator DDR2-1066 2x2GB $109 - $40_rebate = $69
You could even match a 2GB kit with a 4GB kit to fill all four sockets -- this at least would give you memory running at the same spec by the same manufacturer.
The thing I've discovered about these memory specs: some kits can overclock well above the DDR2-800 spec; some DDR2-1000/1066 can underclock well at the same tight latencies of their DDR2-800 counterparts; and some people report that certain makes of the DDR2-1000 don't allow for tighter latencies at the lower speeds.
The CPU : RAM ratios favored by this last generation of CPUs and mobos (with DDR2) are, in descending order of preference: 1:1, 4:5, (and 1;2 with DDR3).
With the Kentsfield quads like your Q6600 G0, you're just not going to make it to a full FSB = 1600 (and DDR=800), even if you come close. So the only way you can squeeze full performance out of the DDR2-1066 is choosing a 4:5 ratio. Per the December, 2007 article here at Anandtech on OC'ing the QX9650 and 45nm Penryn/Yorkfield cores, the 4:5 ratio will pretty much give you a break-even on bandwidth, or even less. It wouldn't be any different from Conroe-Kentsfield.
This means that you can either get DDR2-800's or DDR2-1066's and clock them at 1:1 as close as you can get to DDR=800 Mhz. Then tighten the latencies to the DDR2-800 spec or better.
Now . . . I ain't the extreme over-clocker here, but I've been through about two or three cycles of this since 2003. It was useful in the '90s getting assigned a computer architecture course to teach Asian grad-students, but others may offer equal or better advice. (imHo).
Other advice on the 780i: You may need to bump up the CPU-VTT (CPU-FSB) voltage, but keep it at 1.45V or lower. That's likely if you move into the 375 to 400 CPU-FSB speed range. You may also want to start edging up the 1.2V_HT or MCP voltage (I think that's what the eVGA BIOS calls it, anyway). You should attempt to drop the NB voltage a tad from the "auto" value (which will likely be around 1.45 or 1.5V). Read Graysky's OverClocking sticky.
Use multi-core PRIME95 for initial stability testing -- at least 8 to 10 hours. Then run IntelBurnTest for an hour to two hours. If the core temperatures start moving above 80C, you either need better cooling or a lower clock. That's my cautious judgment. You can then drop the clock back a notch, keeping the same voltage settings. Like I said, read Graysky.