After their first attempt to improve Bulldozer performance through a Windows 7 scheduler was quickly pulled due to performance issues, Microsoft is yet again trying by introducing a new core scheduler update.
As we reported in our original Bulldozer review, AMD made it abundantly apparent that Bulldozer couldn’t realize its full potential under a Windows 7 environment. Their reasoning behind these claims was directed towards Windows 7′s core scheduling which just couldn’t take advantage of the new, advanced architecture. Windows 8 is supposed to do away with many of these issues through the introduction of a new scheduler but Microsoft has now rolled out another update (the first one caused performance issues and was pulled) which is supposed to grant the Bulldozer architecture additional performance improvements under the their current operating system.
More information about the update and a direct download can be found HERE.
There is another essential update for Bulldozer Core Parking (it disabled this feature in Windows) which can be downloaded HERE
Unfortunately, those of you expecting significant, game changing performance will be disappointed. According to AMD’s blog, users can expect AT MOST a 1-2% increase in situations that use half of the processor’s available cores. Heavily threaded applications that use more than four of an FX-8150′s cores, there will be little to no difference after the application of this patch. AMD’s full blog post about this is below:
Some of you may remember that AMD FX processors use a unique dual-core module architecture codenamed “Bulldozer”, which current versions of Windows® 7 were not specifically architected to utilize. In essence, for those with an AMD FX-8150 Processor, for example, Windows 7 sees the eight available cores and randomly assigns threads to them.
In initial testing of the upcoming Windows 8 operating system, we’ve seen performance improvements of up to 10% in some applications, when compared to Windows 7. This is because the system correctly recognizes the AMD FX processor architecture and cores. Thanks to close collaboration between Microsoft and AMD, Microsoft recently completed back-porting some of the Windows 8 scheduler code for AMD FX processors into a hotfix for Windows 7.
So if you have an AMD FX processor, here’s what you can do to update your version of Windows 7:
1) Download the scheduler update (KB2645594) and install. This will tell the schedulerthat your AMD FX processor contains dual-core modules (in fact this is similar to the SMT path that the other guys use). In essence, threads 1-4 now get assigned to their own module first.
2) Download the core parking scheduler update (KB2646060) and install. This will prevent Windows 7 shutting down unused cores prematurely when there are threads to be assigned (there’s a performance penalty parking and then un-parking a core).
The best possible cases for improvement are applications that use ½ cores in your AMD FX processor. In our testing using the AMD FX-8150 processor, we found the best improvement in wPrime, Left 4 Dead 2, and Lost Planet.
Our testing shows that not every application realizes a performance boost. In fact, heavily threaded apps (those designed to use all 8 cores), get little or no uplift from this hotfix – they are already maxing out the processor. In other cases, the uplift averages out to a 1-2 percent uplift.
But heck, it is free performance, and this is the scheduler model that will be used in Windows 8(along with some further enhancements), so why not add it to your list of downloads?
If you have an AMD FX processor, head over to Microsoft and grab the free updates.