Intel 925X Roundup: Creative Engineering 101
by Wesley Fink on August 12, 2004 12:05 AM EST- Posted in
- Motherboards
Foxconn 925A01: Overclocking and Stress Testing
FSB Overclocking Results
| Front Side Bus Overclocking Testbed | ||
| Processor: | Pentium 4 Prescott LGA 775 2.8GHz |
|
| CPU Voltage: | 1.3875V (default) | |
| Cooling: | Thermaltake Jungle 502 | |
| Power Supply: | HiPro 470W | |
| Maximum OC: | 218FSB (+9%) - 100 PCIe or Auto 248FSB (+24%) - 114 PCIe |
|
The LGA 775 processors are multiplier locked, so the only way to overclock the CPU is to increase the FSB. Most of the manufacturers in this roundup float the PCI Express bus and manipulate ratios to achieve higher overclocks. Foxconn takes a different approach by providing a wide adjustment range of fixed PCIe frequencies only. There is no provision to float the PCIe bus.
We were able to confirm the limitations of this approach by reaching a rather dismal 9% overclock with the PCIe fixed at 100. However, we had learned on the DFI and Abit that the nVidia could tolerate a PCIe frequency of at least 114 with simple algorithms or perhaps as high as 120 with more exotic manipulations. So, we set the PCIe to a fixed 114 and started increasing the CPU Clock. With a 114 PCIe, we reached a 248 overclock or 24%. We could not reach any higher, however, with either the ATI X800 XT or the nVidia. Apparently, there is more to the overclocks that others are achieving than just a tales of forced PCIe:CPU ratios. Considering the simplicity of the Foxconn design, however, this is a really excellent overclock that will satisfy many potential 925X shoppers. Just keep in mind that you really have to play with the very sensitive ratios between CPU and PCIe to achieve this kind of overclock on the Foxconn 925x-A01.
Memory Stress Test Results:
The memory stress test measures the ability of the Foxconn 925A01 to operate at its officially supported memory frequency (533MHz DDR2), at the best performing memory timings that Crucial/Micron PC2-4300U will support. Memory stress testing was conducted by running DDR2 at 533MHz (stock 3:4 ratio) with 2 DIMM slots operating in Dual-Channel mode.| Stable DDR533 Timings - 2 DIMMs (2/4 DIMMs - 1 Dual-Channel Bank) |
|
| Clock Speed: | 266MHz |
| Timing Mode: | 3:4 (200:266 - Default) |
| CAS Latency: | 3.0 |
| Bank Interleave: | Auto |
| RAS to CAS Delay: | 3 |
| RAS Precharge: | 3 |
| Cycle Time (tRAS): | 10* |
| Command Rate: | N/A |
The Foxconn matched the other boards in the 925X roundup in being able to run with complete stability at 3-3-3-10 timings with two DDR2 DIMMs. The 925A01 was completely stable at these timings at the default 1.8V.
Filling all four available memory slots is more strenuous on the memory sub-system than testing 2 DDR2 modules on a motherboard.
| Stable DDR533 Timings - 4 DIMMs (4/4 DIMMs - 2 Dual-Channel Banks) |
|
| Clock Speed: | 266MHz |
| Timing Mode: | 3:4 (200:266 - Default) |
| CAS Latency: | 4.0 |
| Bank Interleave: | Auto |
| RAS to CAS Delay: | 4 |
| RAS Precharge: | 3 |
| Cycle Time (tRAS): | 10 |
| Command Rate: | N/A |
When all 4 DDR2 slots are filled, the Foxconn required slightly slower timings than the top boards in the roundup, requiring 4-4-3 timings for complete stability instead of the 4-3-3, which worked well on the Abit, Asus and DFI boards. This is only very slightly slower than the timings on the top 3 boards, and could just as well represent variations in board samples as much as any differences in memory performance with 4 DIMMs.
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jdoor0 - Tuesday, October 26, 2004 - link
This review has been reviewed:http://www.theinquirer.net/?article=18896
Nige - Tuesday, October 12, 2004 - link
Does the ASUS P5AD2 Deluxe motherboard have the same overclocking capability as the P5AD2 Premium?skiboysteve - Friday, August 13, 2004 - link
Wow nice catch. i guess my "(I know... toms sucks)" disclaimer came true.yaeh i understand.
Wesley Fink - Thursday, August 12, 2004 - link
#26 -There is now an apology to Asus up at THG. They measured the voltage wrong. We had also measured the voltage and found 1.5 to 1.55 which is well within spec, not 2.1 as they reported. They now acknowledge the correct voltage measurement for the P5AD2 is 1.53V.
High Northbridge voltage is not the reason the Asus, or any other 925X/915 board, overclocks well. There are far too many simple and wrong explanations for the complex overclocking issues of the 925X/915 chipsets.
skiboysteve - Thursday, August 12, 2004 - link
Page 10"...Broadcom attached to the faster PCI Express bus..."
there is no PCI Express bus, its a point to point protocal.
Just nitpicking.
Great review.
Also, over at Toms (I know... toms sucks) they looked at 9x5 Boards over there and showed that the Asus P5AD2 was running at an astounding 2.1v on the northbridge (1.5v is the stock)
Something might have to be mentioned about reliability of such out of spec behavior, and cooling concerns. You might want to conduct your own quick test on the voltage with a multimeter.
broberts - Thursday, August 12, 2004 - link
One of the problems with these arguments is that the FX-53 is almost 20% more expensive.I've been thinking for a while now that benchmarks should show some form of pricing index so that one can better judge the advantage/disadvantage of the various choices. Just quoting prices isn't ideal, for a host of reasons. I'd suggest, instead, a relative measure. And not just the cost of the particular component being benchmarked. Calculate the cost of the each system used in the benchmarks. Pick one, perhaps the lowest or highest cost one and calculate the relative difference in price. I suggest using the entire system because quite often the choice of one component dictates the available choices for other components. Ideally a relative measure for both the components and entire system would be calculated and published.
manno - Thursday, August 12, 2004 - link
Moo Moo MOO.manno - Thursday, August 12, 2004 - link
why no Doom3?Wesley Fink - Thursday, August 12, 2004 - link
#21 -We will definitely be including Doom 3 benches in future reviews. The only reason they are not included in this 925X roundup is because most of the testing was completed before we had a working copy of Doom 3. You can get a clear idea of how the 925X/Intel 560 performs in Doom 3 in Anand's Doom 3: CPU Battlegrounds review published August 4th at http://www.anandtech.com/cpuchipsets/showdoc.aspx?...
kherman - Thursday, August 12, 2004 - link
Umm, Doom 3 benches?