In your rig specs, you list an ABit 865PE, and you mention the 1:1 memory requirement for PAT, so I assume you are refering to the IS7 (or one of it's variants).
That being the case, if you enable GAT (the "official" name for PAT features on the IS7 since it's a tiny bit different from PAT) then your memory divider and your listed memory timings DO NOT MATTER. GAT sets the timings to what it wants regardless of what you specify in the BIOS.
Here's some info from Mushkin's web site regarding this:
ABIT IS7
ABIT IS7: Intel i865PE Springdale (Intel website)
The ABit IS7 uses a trick to bypass Intel's restrictions on the Springdale chipset, that is, even at the 800 MHz PSB, the additional pipeline stages in the memory address and command path are not activated. This, essentially, turns the Springdale into a pseudo-canterwood with all performance benefits associated with the more expensive Canterwood chipset but no support for ECC. In theory, the Springdale should work similar to the Canterwood, however, keep in mind that the dies used there are not validated for Performance Acceleration Technology. This, in turn, means that there are no guarantees that the performance modes will actually run stable. Because of this "cheat" beyond Intel's specifications, we are only scratching the surface of potential issues and bugs at this point.
With the samples at hand, we still found the IS7 100% compatible with all Mushkin PC3200 and PC3500 Black series. Keep in mind that it is necessary to populate the board with a minimum of two identical DIMMs in the complementary slots in order to get "Dual Channel" performance.
USER TIPS: enabling any of the different performance options will override the manual latency and frequency ratio settings and force a 1:1 CPURAM ratio at 2:x:x:x latency settings, with the "Ultra" (now "F1") setting forcing a 2:2:2:5 latency configuration at DDR400 frequency.
The same issues apply to the IS7 as what we listed for the IC7: using the "Turbo" (or "Street Racer") setting at 2:2:2:7 yields overall better performance since a longer tRAS prevents the controller from inadvertently terminating an ongoing data burst. Enabling the CPC (Command Per Clock) adds another small notch to the overall performance but can cause stability problems as well. The Read Delay timer should be set to 5-6 cycles for best stability and performance or else left on Auto.
We found that DIMMs that require CAS latencies of 2.5 or higher at DDR400 will not function in any of the available performance modes. The workaround is to set the performance tab to "Disabled". Even though this appears counterintuitive at first, it makes sense in that there is no point in reducing chipset latencies when the memory itself would add those latencies again at the back-end of the "food chain". The HW monitor shows voltage values that are below the real voltages, so better not crank them up too much.
Anyhow, bottom line, you should turn off GAT and manually test the timings because depending on what you're setting GAT at, you may be pushing your memory beyond specs without knowing it.