Intel P35 Bearlake Motherboard And DDR3 Memory – Asus and Corsair

It seems like only yesterday we were poking and prodding at DDR2 memory in an effort to see what new-found performance levels we could achieve.  If you recall, in its introductory stages, DDR2 exhibited marginal performance benefits over standard DDR memory, mainly due to its higher latency characteristics in timing and access.  DDR3 will go through much the same development and bring-up cycle.

Corsair XMS3 DHX - CM3X1024-1333C9DHX - DDR3 DRAM Early DDR3 Engineering Samples But Promising

• 667MHz Double Data Rate
  • CL 9-9-9-24 Timings
• 533MHz Double Data Rate
  • CL 7-7-7-21 Timings
• 240 pin notched DIMM
• 1.5V supply voltage
• 8-bit Prefetch
• On-Die Termination

Though all our tests were performed with Corsairs XMS3 CM3X1024-1333C9DHX modules, we also plugged in a pair of CM3X1024-1066C7 modules as well.  Ultimately the Dominator DHX (Dual Path Heat eXchange) sticks you see here offered the best overall performance.  While both sets of DIMMs could handle 1333MHz performance, neither could get below CAS8 timings.  The DHX variety we tested hit CL 8-6-6-15 timings at 1333MHz, which was about as fast as we could go at any voltage.  Incidentally, 1.9V definitely seems to be the sweet spot in terms of overclocking and top-end performance.  More on that subject, later.

Everest  Testing DDR3 Vs. DDR2 Bandwidth And Latency Measurements

We first set out to quickly analyze this new type of memory with Lavalys' EVEREST Cache and Memory Benchmark.  Certain aspects of chipset timings were reporting incorrectly but this didn't affect the performance measurements.

As you can see, we're running a standard Core 2 Duo E6700 chip beyond its rated bus speed at 333MHz for a quad-pumped 1333MHz total FSB speed and 1333MHz DDR3 memory speed.  We then kept the same bus speed but dropped the memory speed down to 1066MHz CL6 and later ran the DDR2 version of the P5K3 motherboard we had, with standard DDR2 memory at 1066MHz CL5.  As you can see, DDR3 at 1333MHz offers the best combination of both raw read/write/copy throughput and latency.  Read bandwidth was on the order of about 7% higher than standard DDR2 on the same chipset (P35) and our latency numbers were shaved down by about 2ns at these speeds, though timings for the DDR3-1333MHz setting were pokey at 8,6,6,15.  Frankly, there is no question this new platform offers measurable gains in performance due in part to the faster memory controller on the P35 chipset, but the high latency characteristics of current DDR3 memory are holding things back quite a bit, as was the case with DDR2 at its inception.  In the months ahead, hopefully manufacturers like Corsair can get timings down closer to CL5 or 6 at 1333MHz.