Implications of disabling the AMD Phenom's TLB patch?

2

I'm currently running a AMD Phenom X4 9600 processor (yeah, it's aging a bit, but other recent problems mean it's not getting upgraded in the immediate future), which happens to be one of the chips that suffer from the TLB errata.

I recall that the first time I played with disabling the TLB patch (probably over a year ago, while playing a game that had a severe performance problem such that it was almost unplayable unless the patch was disabled) I had at least one BSOD, but I can't remeber them being particularly frequent. However, because it decreased instability, I stopped disabling the patch once I was done with the game.

Now, after some recent hardware changes I was experiancing much worse performance than expected from the new hardware under some circumstances, and the TLB jumped to mind - after testing I found that disabling the patch would improve the performance to expected levels.

I'm now wondering if it's worthwhile always having the patch disabled to avoid any potential slowdowns cropping up in the future, or if it is too dangerous. Everything I read states that the bug, when not patched, can causes a system lock-up in "rare circumstances".

So, with the TLB patch disabled:

  • How frequently should system lock-ups be expected?

  • Do we know what the circumstances that trigger the lock-ups are?
    (Don't worry too much about being highly technical, but essentially I wonder if the chip more vunerable under heavy load, or heavy memory usage, etc?)

  • Are there any secondary problems I should be aware of?
    (Don't include things that are charateristic to all lock-ups, please)

DMA57361

Posted 2011-01-10T12:03:37.993

Reputation: 17 581

Answers

2

From AMD Phenom TLB Patch Benchmarked and Explained, quoted from AMD :

It’s unfortunate that the TLB erratum that affects the AMD Phenom 9500 and 9600 processors has garnered as much attention as it has. Unfortunate not just for AMD, but for customers because I believe it has been blown out of proportion. [..] It is extremely unlikely desktop users are going to find themselves in a scenario that could trigger this erratum. [..] We’ve communicated a BIOS modification to motherboard vendors that will ensure system stability, and we’re implementing a silicon fix in future CPUs. But what really stands out to me is that we put a switch in the AMD OverDrive utility that enables PC users to disable the BIOS workaround. That should send a message of our confidence that desktop users should not lose sleep about this particular erratum.

As it says : Don't lose sleep about it.

harrymc

Posted 2011-01-10T12:03:37.993

Reputation: 306 093

Thanks, that's good enough for me. I'll run with the patch disabled for a while, if I hit any real problems I'll update here. – DMA57361 – 2011-01-11T12:11:07.953

Update: I've been using the patch disabled since my last comment and as a result receive maybe one or two BSOD crashes per week, most often while gaming, but otherwise the machine is stable. – DMA57361 – 2011-05-09T13:26:47.913