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OCZ mainstream "Flex" to 1200 MHz or CL3

by on06 March 2007


Review:  OCZ FlexXLC Edition DIMM Kit 2048MB PC2-6400U CL3-4-4-15


OCZ FlexXLC (Xtreme Liquid Convection) DDR2 series is well known name. Although fairly pricy these modules have quality, speed and stability. Compared to the competition they are heavy weight too, in every way. F lexXLC 9200 is not your only choice now, you can go for much cheaper PC2-6400 modules, and at the same time you will overclock them great. 




Ever since the contest on who is going to make faster memory started, OCZ was always among the leaders of the race. We admire hardworking people at OCZ and their constant effort to stay on top but you simply can not neglect the Corsair in the same story. As OCZ never sleeps that wasn’t enough for them. OCZ decided to be even more aggressive from the very beginning of this year. The company entered graphic cards market at the right time with the right product. At the moment NVIDIA has the fastest graphics card on the market and that situation will not change until early May, which counting from today is very long time period.

We still have to wait and see if DAAMIT going to be able to throw NVIDIA of the throne in May. In the meanwhile OCZ will be happy with sales of OCZ 8800GTX that are, besides extremely good memory modules and high quality power supply units, dream of any enthusiast. 


We still remember OCZ FlexXLX PC2-9200 being the first module on the market with 1150MHz speed. Or even better when it was overclocked up to 1280MHz which was impossible speed to reach back then. Today our pet in the shop is Flex XLX PC2-6400 that operates at lowest CL3 latency. Lower lacency means faster memory response and theoretically faster computer.

Main characteristic of any OCZ Flex module is flexibility. FlexXLC can be used without additional cooling systems and that is how we used them in our test. If you are hard core overcloking enthusiast then we recommend water cooling as they are shipped with the hoes.  



FlexXLC PC2-6400 works at 800MHz with CL3 latency or 3-4-4-15 timings. Modules come in pairs, 1GB each. OCZ recommends latest NVIDIA nForce SLI chipset driver  on which modules can profit due to Enhanced Performance Profiles (EPP) that makes them work at CL3 800MHz from the very beginning.  We chose EVGA 680i SLI motherboard with which we have enough of experience already and simply as it is the best memory overclocker board around. Because SPD is pre-programmed in the modules the timings were correct and were at 3-4-4-15. Memory worked at guaranteed 800MHz CL3 and 2.4V.  


We used:

EVGA 680i SLI Motherboard

Intel Conroe Core2 Extreme X6800

OCZ FlexXLC PC2-6400 3-4-4-15 800MHz CL3

Leadtek 8800GTS

OCZ GXS 850W gameXstream  






As we already mentioned FlexXLC PC2-6400 worked perfectly at CL3 latency and 800MHz. We were not able to keep such low latency at 1066MHz , but we managed to have very good CL4 latency with 4-4-4-15 timings and this is a great score itself. Memory worked stable even at this speed and settings.

Front side bus was both tests at 1066MHz and CPU at 2.93GHz. After all of the good results we assumed that OCZ has much more potential so we decided to overclock the CPU. We synchronized raising FSB and memory on to 1200MHz which got CPU to 3.3GHz.





Super Pi




FlexXLC PC2-6400 3-4-4-15 800MHz CPU 2.9GHz


03m 47s

17m 52s

FlexXLC PC2-6400 4-4-4-15 1066MHz CPU 2.9GHz


03m 39s

17m 24s

FlexXLC PC2-6400 5-5-5-15 1200MHz CPU 3.3GHz


03m 19s

15m 24s





Sandra 2007

Memory Bandwith

Memory Latency


FlexXLC PC2-6400 3-4-4-15 800MHz CPU 2.9GHz


76 ns / 73.3

23089MBs /85.9

FlexXLC PC2-6400 4-4-4-15 1066MHz CPU 2.9GHz


70 ns / 68.2

23670MBs /80.5

FlexXLC PC2-6400 5-5-5-15 1200MHz CPU 3.3GHz


66 ns / 71.8

26182MBs /83.8



Super Pi 1MB finished in 15 seconds which is a great score. We usually get 17 as a score even at higher speeds.  In Super Pi 32MB calculations we saved 1 minute and 28 seconds with overclocked system as this is exactly how much we gained from the overclock.  


Sandra shows that overclocking opens new doors for memory as it can work at higher speeds. Memory bandwidth equals to 6411 which is 12% better result compared to the 800MHz clocked memory that scored 5711 in bandwidth test. Latency on overclocked system was lowered to 66ns, on the 800MHz system latency was 76ns.


Games led us to a bit of system instability at 1200MHz but nothing that cannot be solved with a bit of fine tuning. Memory water cooling would be the easiest solution but we had no time to try that one at the moment but we plan to try it out soon.







FlexXLC PC2-6400 3-4-4-15 800MHz CPU 2.9GHz




FlexXLC PC2-6400 4-4-4-15 1066MHz CPU 2.9GHz




FlexXLC PC2-6400 5-5-5-15 1200MHz CPU 3.3GHz








Quake 4




FlexXLC PC2-6400 3-4-4-15 800MHz CPU 2.9GHz




FlexXLC PC2-6400 4-4-4-15 1066MHz CPU 2.9GHz




FlexXLC PC2-6400 5-5-5-15 1200MHz CPU 3.3GHz





Games are a bit tricky. You usually score more with the higher clocked modules and you don’t gain that much from the CL3 at 800. CL4 settings at 1066 can win in fear by an average two to four frames while the 1200 memory at 5-5-5-15 provides up to ten more frames.

Quake 4 at the overclocked system and 3.3 GHz CPU shows some significant improvement as the machine has a lot more horsepower. When you overclock this rather affordable memory to 1200 you can end up with 20 FPS more and eleven percent more performance.


As they cost below €250 in Euroland and about $250 in states this can easily be the best by memory we ever tested. At CL3 it works at 3-4-4-15 DDR 2 800, at CL 4 it works as 4-4-4-15 at 1066 MHz and finally you can reach 1200 MHz with 5-5-5-15 settings and a little effort. This is a great score and we didn’t see such flexibility for a while.

We can easily recommend this memory as it works fast with higher latency or slower but with great latency. There is something there for any of you. We think it is a great memory for the money. Good job boys but we are sure we wil get an email from the competition trying to do something even more sexy. 
Last modified on 06 March 2007
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