The incorrect number of CPUs or Cores are being reported by PerformanceTest
If PerformanceTest doesn't detect the correct number of CPUs in the system or the correct number of cores, then it is likely that the CPU(s) will not be fully loaded during the CPU benchmark, and you'll get poor CPU performance results.
If you are running PerformanceTest then check then check what is reported on the "System" and verify the CPU and core count is correct for your CPU.
The only case we are aware of it not being correct (as of Mar 2011) is when there is a problem in the BIOS configuration.
In some BIOS setup screens you can find a value called something like,
"Max CPUID Value Limit" or "Maximum CPUID Input Value BIOS" or "Limit Maximum CPUID to 3", etc...
This CPUID limit setting needs to be disabled if you are running XP or later.
The technical reason for this is as follows.
CPUID is a low level machine code command that can be executed on the CPU to gather information about the CPU. This information includes details like the make and model of the CPU, the features it supports, cache configuration and the number of cores available.
New CPUs make much more information available about themselves than old CPUs.
Full details for Intel CPUs can be found here,
When Windows boots it queries the CPU to see what level of information is supported (what numbers can be set in the CPU's EAX register). Old operating systems like Windows 98 didn't support a value greater than 3. So to support new CPUs with these old operating system the BIOS developers included this option.
Some programs like PerformanceTest also use the same CPUID instruction to detect the available CPUs and Cores in the machine.
So having this value set wrong can result in wrong system information being reported for newer CPUs and thus lead to performance problems and other strange behavior.
As an example of what might be (incorrectly) reported in PerformanceTest, if this BIOS setting in incorrectly enabled. A Intel Core i7 950 might be reported as having 1 core instead of 4 (or 8 with hyper threading).
CPU is slow all the time
You might be running your CPU in low power mode (which will reduce the clock speed). Check your BIOS settings for this and other incorrect settings (like accidental under-clocking). Also check the power settings in the Windows control panel.
If you are running the ASUS Cool n Quiet feature, consider turning it off in BIOS. According to ASUS this feature can automatically tune CPU voltage and frequency. However running cool and quiet does not equal maximum performance. Maximum performance is often hot and noisy.
Laptop computer is slow all the time
If you are running on battery power you might find things speed up by connecting the PC to mains power. If your PC is in Power Saver Mode you might get at 30 to 40% improvement in the CPU benchmark after changing to High Performance mode. See the "Power options" in the Windows control panel to change this setting.
CPU results are low. But they were OK when Windows was first installed and the CPU has more than 1 core.
After checking power settings and for overheating (see above). Then also check the Windows boot settings. The machine might have been 'tweaked' to run on a reduced number of cores.
Run the configuration utility built into Windows called Msconfig.exe, from the Windows start menu. In the Boot tab select Advanced Options. Then uncheck the "Number of processors" check box. This will allow Windows to autodetect the correct number of CPUs/Cores in the machine.
Your high end SSD drive doesn't get past around 280MB/sec, but according to the specs should be able to run much faster.
Make sure you have connected the SSD drive to a SATA 3 port (6Gbits/sec) and not the slower SATA 2 port (which is only 3 GBit/sec).
Note that older motherboards won't support SATA 3.
After the overheads are taken into account, 3 GBit/sec corresponds to a transfer speed of around 280MBytes/sec
Also check you are in AHCI mode as mentioned above
Wrong or bad PCI-E slot
3D test results are low. Especially for the 'complex' test. Frame rates in games might also be slow.
Make sure your video card is plugged into the correct PCI-E slot on your motherboard. Some MB have various PCI-E slots that run at different speeds (lane counts, x1, x2, x8, x16).
For PCI-E the lane count is automatically negotiated during device initialization, and can be restricted by either endpoint. For example, a single-lane PCIe (×1) card can be inserted into a multi-lane slot (×4, ×8, etc.), and the initialization cycle auto-negotiates the highest mutually supported lane count. The link can dynamically down-configure the link to use fewer lanes, thus providing some measure of failure tolerance in the presence of bad or unreliable lanes
Bad lanes or dirty connectors on your video card or motherboard can result in some of these lanes being disabled.
In the CPU-Z software there is a "link width" display. So check that out and see what you are now running at. For example it should be x16 if that is what your video card and MB support.
For most applications the difference in bandwidth between x8 and x16 isn't important, as x8 is enough most of the time. Being stuck at x1 or x2 however can be very noticeable.
Possible solutions include BIOS updates and re-seating the video card.
AMD Fusion CPU bug
Integer maths test and Prime number test give very low results. About 80% lower than expected. All other tests are give the expected benchmark results and you have an AMD Fusion Llano CPU.
We believe this is related to a CPU bug.
At the time of writing this seems to effect about half of the CPUs when run in our CPU benchmark.
The bug itself can cause the CPU to hang or behave unpredictably while doing division operations. The workaround AMD suggested is to patch the CPU, which reduces the CPU performance to avoid the hang. The patch should be applied in BIOS. But only half the motherboard manufacturers have applied it from what we can see (as of April 2012).
AMD Fusion Llano CPUs include the A4-3300, A6-3500, A6-3600, A6-3650, A8-3800, A8-3850, Athlon II X4 641, AMD Athlon II X4 651 and a few others.
This problem will be reduced (slightly more hidden) in PerformanceTest version 8 where we will do less division.
For more details, see this post,
Spyware, Adware, Antivirus and Msconfig comments
Regarding 4 and 6:
Originally Posted by Brian
After 30 years of dealing with spyware, adware, and anti-viruses on Apples, Macs, and PCs, I have decided to stick with Microsoft's Security Essentials. Personally, I have been dissatisfied with both products suggested in 4.
Be really careful in disabling items using msconfig. As an example, you could end up with no sound. While it is true a lot of items can be disabled, you really need to know what you are disabling. In reality, if you have a newer machine with lots of memory, startup is minimally affected.
2D results with remote desktops
2D results are low compared to other some other baselines. (Or put another way, some machine's have 2D results that are too high).
We have seen a small number of baselines with very high 2D results in V7 of PerformanceTest. Roughly 10x faster than normal. e.g. Solid vector scores of 22.0 instead of 2.1
It turns out that running PerformanceTest across some remote desktop solutions gives higher than expected 2D performance. This isn't a real performance increase, the video driver is instead throwing away some requests to update the screen, making it seem to the application that updates are running faster than they actually are.
DirectX 9 3D test gives low results
The DirectX 9 complex test gives low 3D frame rate results (~30% down) compared to similar machines.
The Morphological filtering (also know as MLAA) setting might be turned on the video card's device driver control panel. This issue was seen with HD 6850 video card, but probably effects most cards.
Morphological filtering is a technique that applies full screen anti-aliasing, which can improve the smoothness and quality of rendered images.