OCZ Reaper Heat Pipe Conduit DDR2
Overclocking
Except for the cooling solutions they use, the Reaper HPC line-up is very similar to the Flex XLC series and memory modules belonging to either series utilize the extremely popular Micron D9GMH memory chips. Considering their similarity, we expect the Reapers to overclock well, just like the Flex XLCs did.
All of our overclocking was done on the NVIDIA 680i SLI platform since it allows pseudo-synchronous memory clocking. This means we can overclock the memory without changing the FSB frequency, which eliminates a potential bottleneck. It also means that the CPU clock is not affected by the memory overclock, allowing direct performance comparisons to be made in benchmarks since memory benchmarks are somewhat effected by the CPU. All of our overclocking was done with the FSB locked to stock frequencies.
Reaper HPC PC2-8500 @ 1143MHz & CAS 5-5-5-15
First up is the Reaper HPC PC2-8500. These modules are rated for a stock frequency of 1066MHz at CAS 5-5-5-15 with a stock voltage of 2.3V. OCZ provides Extended Voltage Protection (EVP) on all Reaper HPC memory, which allows their voltages to be increased to a specified limit without invalidating their lifetime warranty. The EVP limit varies from model to model and the PC2-8500 have an EVP of 2.35V. For all of our overclocking, we did not exceed the specified EVP voltage for the memory modules since most people probably aren't too keen on voiding their lifetime warranty. Unfortunetly, in this case, this restriction only gives us an extra 0.05V over the stock voltage to work with due to the module's already high stock voltage.
The highest overclock we were able to coax out of our particular Reaper HPC PC2-8500 modules was 1143MHz at the EVP voltage of 2.35V. At this speed, the modules were able to maintain stock timings. Any attempt to lower the timings or push the frequency higher resulted in significant instability. While this isn't a poor result, it certainly isn't special. It is relatively common for high-end PC2-8500 memory kits to reach overclocks of 1150MHz with nothing more than a minor voltage adjustment. However, we understand that overclocking results are very much a luck-of-the-draw type of deal so we took a quick look around the 'net to get an idea of what kind of results other people were getting with their Reaper HPC PC2-8500 modules. It seems that we were somewhat unlucky with our particular Reaper HPC PC2-8500 modules since our overclock was lower than many of those being reported around the net.
Reaper HPC PC2-6400 EB @ 1067MHz & CAS 4-5-5-15
We had a bit more luck with our Reaper HPC PC2-6400 Enhanced Bandwidth edition modules. These modules are rated for 800MHz with timings of 4-3-3-15 at a stock voltage of 2.0V. We were able to push our particular modules to a stable 1067MHz with a timing of 4-5-5-15 at the EVP voltage of 2.2V. With this overclock, the modules were able to run through our gauntlet of benchmarks several times without incident. We were able to get our test system to boot into windows at higher frequencies, but the system couldn't make it all the way through a run of PCMark05 without crashing; not exactly what we would call stable. Additionally, increasing the memory timings to 5-5-5-15 did not give us any more leway with frequency.
Our result in this case is quite impressive. Our overclocked Reaper HPC PC2-6400 EB modules are superior to stock Reaper HPC PC2-8500 modules in many ways, with lower voltage, tighter timings and a lower price. A quick look around the 'net shows that our results are pretty typical and many other people are achieving similar overclocks although, as always, your milage may vary.
All of our overclocking was done on the NVIDIA 680i SLI platform since it allows pseudo-synchronous memory clocking. This means we can overclock the memory without changing the FSB frequency, which eliminates a potential bottleneck. It also means that the CPU clock is not affected by the memory overclock, allowing direct performance comparisons to be made in benchmarks since memory benchmarks are somewhat effected by the CPU. All of our overclocking was done with the FSB locked to stock frequencies.
Reaper HPC PC2-8500 @ 1143MHz & CAS 5-5-5-15
First up is the Reaper HPC PC2-8500. These modules are rated for a stock frequency of 1066MHz at CAS 5-5-5-15 with a stock voltage of 2.3V. OCZ provides Extended Voltage Protection (EVP) on all Reaper HPC memory, which allows their voltages to be increased to a specified limit without invalidating their lifetime warranty. The EVP limit varies from model to model and the PC2-8500 have an EVP of 2.35V. For all of our overclocking, we did not exceed the specified EVP voltage for the memory modules since most people probably aren't too keen on voiding their lifetime warranty. Unfortunetly, in this case, this restriction only gives us an extra 0.05V over the stock voltage to work with due to the module's already high stock voltage.
The highest overclock we were able to coax out of our particular Reaper HPC PC2-8500 modules was 1143MHz at the EVP voltage of 2.35V. At this speed, the modules were able to maintain stock timings. Any attempt to lower the timings or push the frequency higher resulted in significant instability. While this isn't a poor result, it certainly isn't special. It is relatively common for high-end PC2-8500 memory kits to reach overclocks of 1150MHz with nothing more than a minor voltage adjustment. However, we understand that overclocking results are very much a luck-of-the-draw type of deal so we took a quick look around the 'net to get an idea of what kind of results other people were getting with their Reaper HPC PC2-8500 modules. It seems that we were somewhat unlucky with our particular Reaper HPC PC2-8500 modules since our overclock was lower than many of those being reported around the net.
Reaper HPC PC2-6400 EB @ 1067MHz & CAS 4-5-5-15
We had a bit more luck with our Reaper HPC PC2-6400 Enhanced Bandwidth edition modules. These modules are rated for 800MHz with timings of 4-3-3-15 at a stock voltage of 2.0V. We were able to push our particular modules to a stable 1067MHz with a timing of 4-5-5-15 at the EVP voltage of 2.2V. With this overclock, the modules were able to run through our gauntlet of benchmarks several times without incident. We were able to get our test system to boot into windows at higher frequencies, but the system couldn't make it all the way through a run of PCMark05 without crashing; not exactly what we would call stable. Additionally, increasing the memory timings to 5-5-5-15 did not give us any more leway with frequency.
Our result in this case is quite impressive. Our overclocked Reaper HPC PC2-6400 EB modules are superior to stock Reaper HPC PC2-8500 modules in many ways, with lower voltage, tighter timings and a lower price. A quick look around the 'net shows that our results are pretty typical and many other people are achieving similar overclocks although, as always, your milage may vary.
