Review By Steve Angelly - September 28, 2005 Edited by Jonathan Martini
The 220 MHz FSB frequency is the overclocking limit for my P4 3.4E (550) processor. This also happens to be the 10% overclock limit as found on many Intel chipsets and the various Intel chipsets from other manufacturers including NVIDIA.
The posted CPU-Z result demonstrates the maximum FSB limit of 220MHz with the ram running at 667MHz, 4-4-4-12, 1T was it. This overclock setting provided good solid gameplay and all-around performance but any attempt to increase the FSB past the 220 MHz mark was met with a hard lock.
The best explanation I found was at Hardware Secrets in their article, 'How to Overclock a Socket 775 Pentium 4.' The article explains that this barrier occurs because the various buses, such as the PCI Express bus, SATA, and the link between the chipset's north and south bridges use the same clock generator with frequencies varying according to the clock used. This causes problems to arise with SATA and PCI Express devices, since there is no way of locking the frequencies of these devices. SATA devices, for example, have problems in working at frequencies higher than 110MHz, and NVIDIA video cards tolerate the maximum of 120MHz on PCI Express bus.
Should the listed arguments be true, then I am relegated to either changing out the CPU with one that does not have locked multipliers, going back to using IDE drives for the main HDD, and/or upping the voltages. These options are either not possible, or acceptable, to me at the present time. Therefore I will just back the overclock to a 215MHz FSB which provides a little head room or just run default settings which are very acceptable for present games.
The 215MHz FSB setting increased the performance in most synthetic benchmarks by 5-6% and provided good game play in Far Cry at 1600x1200, 4xAA/8xAF.
I was able to set the memory frequency in the bios to 800MHz which gave a slight increase in bandwidth as revealed by Sandra. The downside was that running at this high memory speed limited the memory timings to 2T, at 4-4-4-12, 333MHz frequency. This applied to the use of either Crucial Balistix PC5300 or Corsair DDR2 XMS Extreme PC5300.
At 1T, 4-4-4-12, 333MHz, the FSB was still limited to 220MHz and changing to Corsair XMS PC5300 did not improve stability.Lowering the FSB to 215-217MHz range provided good stability in all apps and games.
Corsair XMS Extreme PC5300
Crucial Balistix PC5300
SiSoft Sandra records the bandwidth of the current system at 4940 MB/s Int Buff'd iSSE2 and 4923 MB/s Float Buff'd iSSE2.
CPU-Z - 2GB Memory Timings
Interestingly, using both Crucial and Corsair DDR2 PC5300-rated memory modules to populate all 4 DIMM slots provided dual channel capability with the same stability and performance at 1T, 4-4-4-12, 333MHz, as well as providing a full 2GHz of system ram. Although I do not recommend using mixed memory, I have had no issues with the current setup as it is providing excellent game play in Battlefield 2.