Here's a summary of our overclocking joy ride with the OCZ Flex II 4GB DDR2 kit. 

It seems that there's a MHz ceiling for this pair of RAMs when operating at CL4. We weren't able to go higher than 933MHz irregardless of what Vdimm we used. However, running 933MHz on CL4 is commendable because we're doing it this time on a 4GB kit, rather than a 2GB product.

CL5 performance was much better, with this pair of memory crossing the 1200MHz mark at all three test voltages. Again, this should be noted because being able to overclock past 1200MHz, or even near 1200MHz on 4GB kits (2GB sticks) is very rare. The OCZ even managed to get quite large number of MHz over 1200 when fed with 2.30V of Vdimm.

The Flex II memories run cool even when loaded. We had a low RPM fan blowing over the RAM area, and at 2.30V on high frequencies, the memory sticks were just barely warm to the touch.

High capacity 4GB kits on higher density chips are still relatively new to the market. The chips used for these products are likely to play catch-up in overclocking, since 2GB kits have been around for a long time and some have ample overclocking headroom.

Keeping in mind that 4GB performance kits are only starting to emerge, the OCZ DDR2 PC2-9200 Flex II 4GB kit offers excellent out of the box performance at 1150MHz, and yet still has headroom to clear 1200MHz and reach a maximum frequency of 1236MHz. That said, not many 2GB kits are able to clear 1200MHz comfortably either.

If you're interested in high freqency and low latency, 2GB kits are still the way to go. It would take some time before 4GB kits can have comparable overclocking traits of their 2GB brothers. However, if you're not looking for waist-compressing tight latencies, the OCZ Flex II 4GB kit might just be the one for you. It has capacity (all 4GB of it), and it has the speed (1236MHz) to boot. Even if you were to use the factory spec-ed Vdimm of 2.10V, you can still clear 1200MHz, something that few 4GB kits can do.

Blessed with speed, capacity and even a watercooling option, the OCZ DD2 PC2-9200 Flex II 4GB gets our recommendation to anyone who is looking to build a high performance system without breaking the bank on memories.