P55 OverclockingThe phase change is down to about -30C, the timings set, the OS setup...there is nothing left to do but see how the memory clocks.  Unfortunately, this discussion is going to revolve around caveats starting with the top red result. Obviously the memory clocks didn't increase, but this is absolutely not a limitation of the memory. In fact, the voltage of 1.65v listed is rather misleading, this motherboard completely hates us. With newer BIOS's the memory clocks have absolutely gotten worse with our sample and the i7 860 processor we have paired with it. Check the screen shots below for the 1100MHz 8-8-8 result, it was actually achieved at 1.56v!
At CL6 and CL7, these sticks really clock well except at 7-7-6. We fought with this timing combination for a long time but just couldn't get 7-7-6 to scale with volts much at all. As we can see, it starts out actually clocking higher than the 7-8-7 timing set but fails to improve with voltage. 7-8-7 clocks right up to a very healthy 1086MHz, almost equal with 8-8-8. DDR3-2172 at 7-8-7 with only 1.75v is very nice indeed. So far the Dominator GTX2 modules have performed as expected.
As good as the results are, we have to absolutely bring this up. The numbers achieved here are fantastic, don't get us wrong, but they are also on par with any other PC3-16000+ kit of memory that uses Elpida Hyper IC's. Some triple channel kits that cost as much or significantly less than two sticks of these Dominator GTX2 modules will overclock just as well. The other thing we want to say is that we did do some testing on our first set of memory received with the poor heat sink application. Before sending them back we achieved much better results than is the case with these modules. These particular sticks do not like to run 6-6-5 where as our last kit clocked 6-6-5 almost as well as 6-7-6. In addition, the other pair clocked 7-7-6 better than this pair clocks 7-8-7. That is the probably the greater reason for our disappointment. Despite the high price tag, the Dominator GTX modules still appear to have a wide range of capabilities while we hoped they would be binned to near-perfection. It really was a night and day difference between the second set of modules we received and the first. The last thing you want to be hoping for with a $200 stick of ram is whether or not it is going to be great...they should all be better than great in our opinion. Like everything in overclocking, however, it comes down to luck of the draw.
Here are the screen shots of the runs at 1.75v... 6-7-5 Overclock @ 1.75v
click for full size...
CMGTX2 @ 950MHz 6-7-5-18 1T
@ 1.751v under load | 7-7-6 Overclock @ 1.75v
click for full size...
CMGTX2 @ 1059MHz 7-7-6-20 1T
@ 1.751v under load | 7-8-7 Overclock @ 1.75v
click for full size...
CMGTX2 @ 1086MHz 7-8-7-20 1T
@ 1.751v under load | 8-8-8 Overclock @ 1.56v
click for full size...
CMGTX2 @ 1098MHz 8-8-8-20 1T
@ 1.563v under load |
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