ATI 9100 IGP PRO: Optimized for Prescott

ATI 9100 IGP PRO: Overclocking and Memory Stress Tests

FSB Overclocking

One question that we could not answer in our tests of the RS350 Reference Board was whether ATI had fixed the overclocking complaints many had with the earlier RS300. ATI assures us that the RS350 is now a competitive overclocker with the Intel 865G chipset, which would certainly be a dramatic improvement compared to the dismal overclocking abilities of the RS300. However, the RS350 Reference Board, like most Reference Boards we test, was not really designed for overclocking. With no FSB adjustments and no voltage adjustments available at all on the board, we could not verify ATI's claims about overclocking.

When Radeon 9100 IGP PRO boards begin shipping, we will take a closer look at the chipset's overclocking abilities. As much as the RS350 is improved over the original, overclockers will expect the ATI chipset to perform just as well at overclocking as the Intel 865/875 family chipsets. This feature will be very important to them, but will not matter very much to those who do not overclock their systems.

Memory Stress Testing

We performed memory stress tests on the Radeon 9100 IGP PRO Reference Board. This memory stress test simply tests the ability of the RS350 Reference Board to operate at its officially supported memory frequency (400MHz DDR) at the lowest supported memory timings our Mushkin PC3500 Level 2 memory will support:

Stable DDR400 Timings - 2 DIMMs (One Dual-Channel Bank 2/4 DIMMs populated)
Clock Speed:	200MHz
Timing Mode:	N/A
CAS Latency:	2.0
Bank Interleave:	N/A
RAS to CAS Delay:	3T
RAS Precharge:	5T
Precharge Delay:	2T
Command Rate:	N/A

While we had stability issues running at the most aggressive 2-2-2-5 timings that our memory would support, we had no problem running 2 DS 512MB DIMMs of our standard Mushkin PC3500 Level 2 with complete stability at 2-2-3-5 timings. This meant adjusting RAS-to-CAS timings to 3 instead of the fastest 2 setting. Performance at these timings should be very close to that achieved with 2-2-2-5 timings. ATI tells us that these are probably the most aggressive timings that could be achieved with the Reference Board, but that the shipping 9100 IGP PRO will likely be capable of the most aggressive timings we have been able to use on Intel chipsets.

Filling all available memory banks to populate two dual-channel banks is more strenuous on the memory subsystem than testing 2 DIMMs. 4 x 512MB DIMMs in 2 DC banks, a total of 2 GB of memory, worked just fine on the RS350. We were able to use the same timings for stable operation with 4 DIMMs that worked with 2 DIMMs.

Stable DDR400 Timings - 4 DIMMs (Two Dual-Channel Banks 4/4 DIMMs populated)
Clock Speed:	200MHz
Timing Mode:	N/A
CAS Latency:	2.0
Bank Interleave:	N/A
RAS to CAS Delay:	3T
RAS Precharge:	5T
Precharge Delay:	2T
Command Rate:	N/A

We tested the memory timings with both 2 and 4 DIMMs using several stress tests and general applications to guarantee stability. Prime95 torture tests were successfully run at the timings listed in the above charts. We also ran ScienceMark (memory tests only) and Super Pi. None of the three stress tests created any stability problems for the ATI RS350 Reference Board at these memory timings.