OCZ EL PC2-8000 XTC: Low Latency PLUS DDR2-1100
by Wesley Fink on April 3, 2006 12:01 AM EST- Posted in
- Memory
Overclocking Performance
We were able to overclock using the DDR2-533, DDR2-667, DDR2-711, DDR2-800, DDR2-889, or DDR2-1066 memory straps. Since the Presler 955 Extreme Edition processor utilizes a 1066 MHz bus speed it allows us to use the 1:1 memory to FSB clock ratio when the front side bus speed is set to 266 MHz. Keep in mind that the Intel FSB is quad-pumped, which is why a setting of 266 yields a FSB of 1066 (4x266). DDR2 Memory on the Intel platform, however, is by definition Double Data Rate, so a 266 base setting is 533 (2x266). The dual-channel setups used in nearly all systems keep the bandwidths matched, however, given 2 x DDR2-533 bandwidth.
The chart above indicates relative scaling with front side bus speed increases from a 1:1 memory strap (DDR2-533). SiSoft Sandra Professional Buffered and Unbuffered memory scoring were both included in benchmarking, along with SuperPi time to calculate 2 million places in seconds. The Half Life 2: Lost Coast benchmark was run at 1024x768 resolution at maximum quality settings with HDR on. Far Cry was set for ultra quality in the settings with a resolution of 1024 x 768.
Using the stock 13X multiplier of the 955 EE Presler, we were able to hit 352 FSB at the lowest timings of 3-3-3-11. While higher 1:1 settings were possible, they were not completely stable with our air-cooling setup. That makes the CPU the likely road block to further overclocking with an effective limitation of about 4.5GHz on stock air cooling.
The OCZ PC2-8000 operated with no heat problems up to 2.2V, which covered the majority of benchmarking. Above 2.2 the memory heats up quickly and performs best with an auxiliary fan cooling the memory.
We were able to overclock using the DDR2-533, DDR2-667, DDR2-711, DDR2-800, DDR2-889, or DDR2-1066 memory straps. Since the Presler 955 Extreme Edition processor utilizes a 1066 MHz bus speed it allows us to use the 1:1 memory to FSB clock ratio when the front side bus speed is set to 266 MHz. Keep in mind that the Intel FSB is quad-pumped, which is why a setting of 266 yields a FSB of 1066 (4x266). DDR2 Memory on the Intel platform, however, is by definition Double Data Rate, so a 266 base setting is 533 (2x266). The dual-channel setups used in nearly all systems keep the bandwidths matched, however, given 2 x DDR2-533 bandwidth.
| OCZ EL PC2-8000 XTC (1:1 Memory Ratio) - 2x1GB Double-Bank | |||||||
| CPU Settings |
Memory Speed (1:1) |
Best Memory Timings (Voltage) |
Far Cry (fps) |
Sandra Unbuffered |
Sandra Standard Buffered |
SuperPi Mod 1.4 2M places (time in sec) |
Half Life 2: Lost Coast (fps) |
| 13x267 | 533 DDR2 |
3-2-2-9 1T 2.1V |
63.1 | INT 3570 FLT 3600 |
INT 6500 FLT 6498 |
85 | 84.2 |
| 13x333 | 667 DDR2 |
3-2-3-11 1T 2.1V |
73.9 | INT 4368 FLT 4414 |
INT 8108 FLT 8097 |
68.1 | 106.3 |
| 13x352 | 704 DDR2 |
3-3-3-11 1T 2.2V |
83 | INT 4512 FLT 4630 |
INT 8494 FLT 8504 |
64.9 | 109.8 |
The chart above indicates relative scaling with front side bus speed increases from a 1:1 memory strap (DDR2-533). SiSoft Sandra Professional Buffered and Unbuffered memory scoring were both included in benchmarking, along with SuperPi time to calculate 2 million places in seconds. The Half Life 2: Lost Coast benchmark was run at 1024x768 resolution at maximum quality settings with HDR on. Far Cry was set for ultra quality in the settings with a resolution of 1024 x 768.
Using the stock 13X multiplier of the 955 EE Presler, we were able to hit 352 FSB at the lowest timings of 3-3-3-11. While higher 1:1 settings were possible, they were not completely stable with our air-cooling setup. That makes the CPU the likely road block to further overclocking with an effective limitation of about 4.5GHz on stock air cooling.
The OCZ PC2-8000 operated with no heat problems up to 2.2V, which covered the majority of benchmarking. Above 2.2 the memory heats up quickly and performs best with an auxiliary fan cooling the memory.
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DoctorBooze - Tuesday, April 4, 2006 - link
I'm a bit mystified why there's any better performance at any speed over dual-channel DDR2-533 - is it just because the CPU ended up overclocked?Am I right in thinking that CAS 2 for DDR2-533 is the same amount of time as CAS 4 for DDR2-1066?
Also, what's performance like with a single-channel setup using DDR2-1066 since that would also theoretically be a 1:1 configuration, wouldn't it?
Calin - Wednesday, April 5, 2006 - link
The improved performance is based on the fact that RAM is no longer random access memory - it is faster to bring several kilobytes of data forming a single block than to bring several kilobytes of data from separated areas of the memory. And, while the speed to bring 1024 bytes, each 4 bytes from a different area of the memory means that each access is made with delay of (CAS2 + RAS2 + ... + tRAS) multiplied by memory clock is the same as CAS4 + RAS4 + ... + tRAS for a memory that has twice the speed, if you bring a single block, you only need CAS and RAS once, and the rest comes at memory clock, one block at a clock. So, if you make long transfers, you can almost forget about CAS and RAS, and only use the memory speed.So, faster memory with higher CAS (Column Address Select) and RAS (Row Adress Select) timings will still move loads of data faster, even if single bytes will go as fast as with slower memory with lower CAS and RAS
What is CAS and RAS?
A memory is a huge space of addresses. However, you can not access all those addresses at the same time - memory is accessed in blocks formed by rows and columns. In order to access data from memory, you must be in the correct block (row and column). Once in a block, the data from memory can be read by simple commands (selection of address). If the row, column or both changes, the memory must change the block it shows - so, here are the CAS and RAS timings needed for the memory to select a different block.
Visual - Tuesday, April 4, 2006 - link
... or amasingly complexim just standing here and boggling at the complexity of overclocking intel systems. well, it turns out just as simple as amd when i think about it, but the mem ratios that allow the ram to run faster than the cpu fsb (as opposed to only slower like on the athlons) kinda make it too weird to assimilate :p
and with ratios,fsb/cpu/mem frequencies,timings and whatnot to consider at once it does get messy for someone unexperienced like me.
its interesting to see the significant performance differences that the proper settings can bring. in particular, it looks like with a fast memory like this and a proper oc one can get a good 20-30% above stock in gaming performance, and so can match amd systems even with the netburst cpus. who made me think netburst was dead?
also it makes me think if the conroe benches weren't ran with something like this - very fast memory, low latencies, overclocked fsb. cant be bothered to look for your old article on it though, i'll just wait for the next benches to come up.
Calin - Wednesday, April 5, 2006 - link
My ECS K7S5A (built somewhere in 2002 probably) could run my Duron 600 processor at 100 or 133 FSB, and the memory at 100 or 133 FSB for SDR or 200 and 266 for DDR, independent on each other.This is not something new. I remember older systems having the same possibilities.
The Athlons (Socket A Athlons) were able to run memory faster than the FSB, however, there was an important performance loss because of the increased latency. In some cases, an Athlon on 100MHz FSB was slower with 133MHz memory than with 100MHz memory, as the increased bandwidth advantage was negated by increase in latency
Jjoshua2 - Monday, April 3, 2006 - link
On page three HL2 is reported as over 850 fps on 1:2.Wesley Fink - Monday, April 3, 2006 - link
We reran and updated the Half life 2 - Lost Coast results after the article was published. The enthusiastic typing error is now corrected.Barbarossa - Monday, April 3, 2006 - link
Wow, looks fast. I have to wonder if it's available anywhere though. I followed all your links at the top of the article, but those take me to different parts than the one you reviewed, and a quick search at Newegg, ZipZoomFly, and TigerDirect shows that nobody has it in stock.Does this part actually exist or is this just a cherry-picked press release part?
Wesley Fink - Monday, April 3, 2006 - link
This memory is currently available at Atacom.com and possibly other sites. More info is at http://www.atacom.com/program/print_html_new.cgi?c...">http://www.atacom.com/program/print_htm...m_code=M....It is incredibly expensive at $560 for the 2GB kit.
JarredWalton - Monday, April 3, 2006 - link
It's a brand new part, and it's not yet in our pricing engine. The links at the top are generated by key words from our pricing engine and do not always bring up the appropriate parts. The part numbers you'll want are:1x512: OCZ2P1000512EE
2x512: OCZ2P10001GEEK
1x1024: OCZ2P10001GEE
2x1024: OCZ2P10002GEEK
Availability should commence shortly.
Missing Ghost - Monday, April 3, 2006 - link
lmao