The GEIL G31GB1066C6PXA pair (2x 1GB) has performed as to its specification and runs well beyond the 1066 mark. In fact, running at 1333 is well recommended. During our tests, we noticed that lowering the CAS latency wouldn't help much in the performance. Running a board with SYNC clks are still the best to give you a thoughput of 8000+ MB/s. Using ASYnc settings and pushing numbers beyond 1066, 1333, 1500 without the CPU running in SYNC doesn't make good of the bandwidth of the modules.

Nevertheless, the modules are here. If you intend to get higher bandwidth with async settings, this DDR3 module is recommended as we see it has a slight advantage in speed over the others which are rated at a slower speed.

For more information, please refer to the below website:

http://www.ocworkbench.com/2007/geil/ddr3-1066/g1.htm