Brief P45 Bandwidth Testing

[CryptiK]

I thought I'd investigate the bandwidth and latency achievable using the P45 chipset. The P45 is getting a reputation for low clock for clock efficiency compared to its predecessor, the P35, and the performance designed X38/X48 chipset. I tested a few combinations of FSB, ram speed and tRD to see what the P45 could do, and did a brief comparison with an X38 chipset (Thanks to Grnfinger for running the X38 tests ).

Board: Maximus II Formula, Bios 1307 (604 in first SS)
CPU: e8400
Ram: TeamXtreem 8500 (GMH) / CellShock 8000 CL4 (GKX)

445 FSB, 4GHz, 556.5 MHz CL 5, tRD 8 (my 24/7 settings)


450 FSB, 3.6GHz, 600 MHz CL 5, tRD 8


500 FSB, 4GHz, 600 MHz CL 5, tRD 8


505 FSB, 4.04GHz, 606 MHz CL 5, tRD 8


530 FSB, 3.97GHz, 635.7 MHz CL 5, tRD 8


550 FSB, 3.85GHz, 660 MHz CL 5, tRD 8 (best bandwidth and latency I have achieved so far, not bad for a P45 )


434 FSB, 3.9GHz, 651 MHz, CL 5, tRD 6


439 FSB, 3.95GHz, 658.6 MHz, CL 5, tRD 7


539 FSB, 3.9GHz, 539 MHz, CL 4, tRD 10


570 FSB, 3.9GHz, 570 MHz, CL 5, tRD 10


Comparison to Grnfinger's X38 chipset (not using same memory modules and some slight difference in secondary timings but same Primary timings & FSB). I used lowest bootable tRD for each test.



The P45 can pull some decent numbers, I was pretty happy to get 11K across the board in everest.

In comparison to the X38, the P45 has a lower read bandwidth, but higher write and higher copy bandwidth. The X38 also has a lower latency at any given FSB/ram speed combination. Would these differences be evident in day to day usage, like gaming etc? I doubt it, and from my testing and personal experience I think the P45 is a decent mid range chipset, and if there is no need to step up to the X48 chipset (ie: no requirement for two 16x PCI-E slots when both slots are populated), the P45 looks to be a good balance between performance and price.