I’ve been waiting weeks for my reseller to receive stock on the CPU. I kicked myself for not purchasing it earlier from another reseller, as it fell to a low of $199, and recently the price surged to $260 due to a shortage of the CPU’s. I managed to acquire it for $222, which was a price I was willing to pay.

The Core 2 Duo E8400 is one of Intel’s first 45 nm CPU’s. Intel’s 45 nm CPU’s consume less power and run cooler than their 65 nm (Conroe) counterparts. They are also very overclockable. The CPU (stock) is currently running at 24C, which is significantly cooler than my E6400 at 40C.

I ran wPrime v1.61 to compare the computing power of both CPU’s. wPrime is a multithreaded benchmark that calculates the square-roots of large amounts of numbers — 32 million in this case. For this benchmark, I used Gigabyte’s P35-DS3L v2.0 motherboard (BIOS revision: F8b).

Intel Core 2 Duo E8400 (3.00 GHz): 32M test completed in 26.952 seconds.
Intel Core 2 Duo E6400 (2.13 GHz): 32M test completed in 41.297 seconds.

I realize it’s not a fair clock-for-clock comparison, but it shows the sheer computing power of each CPU. Simple math shows us that the E8400 should be approximately 29% faster than the E6400. The E8400 beat the E6400 by a significant margin (as expected), 34.7%, using a combination of higher clock speed, a faster FSB (1333 MHz vs 1066 MHz) and more L2 cache (6 MB vs 2 MB).

Given the price point of the new Intel 45 nm CPU’s (T8xxx/T9xxx), I recommend waiting out and purchasing them over the current Conroe / 65 nm CPU’s (T5xxx/T7xxx).

Specifically, I was eager to determine the maximum memory bandwidth I could attain using DDR2-553 memory timings (4-4-4-12 stock), while acknowledging that the ASRock 775Dual-VSTA performs poorly with the standard DDR2-667 memory timings (5-5-5-12 stock). Hence, all tests below were completed with the memory timings set to DDR2-533. EVEREST Ultimate Edition 2006 was the benchmark utility of choice. CPU used: Intel Core 2 Duo E6400 (stock configuration with Arctic Cooling Freezer 7 Pro HSF).

Test 1 (CL-tRCD-tRP-tRAS):
4-4-4-12, CR: 2T
Memory Bandwidth (Read): 10,136 MB/s

Test 2:
3-3-3-8, CR: 2T
Memory Bandwidth (Read): 11,274 MB/s

Test 3:
3-3-3-8, CR: 1T
Memory Bandwidth (Read): 11,785 MB/s

Surprisingly, the Mushkin memory kit ran using a command rate of 1T using DDR2-533 timings! In contrast, I could only squeeze about 9.9 GB/s of bandwidth using DDR2-667 stock timings.

I also tested the integer performance of the Intel Core 2 Duo E6400 (2 x 2.13 GHz) and the AMD X2 4200+ (2 x 2.2 GHz) CPU, both running at stock configuration. The motherboard used for the X2 4200+ was the ASRock 939DUAL-SATA2. Benchmark: SuperPi – 1.1e — displays the time required to calculate a specified number of digits of Pi.

Intel Core 2 Duo E6400 vs AMD X2 4200+ S939
512K – 10 seconds | 512K – 18 seconds
1M – 26 seconds | 1M – 40 seconds

The E6400 is clocked at 2.13 GHz, with the X2 4200+ clocked at 2.2 GHz. However, even with the deficit in speed, the E6400 can outperform the X2 4200+ by more than 45%.