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-   -   What is the PerfLevelSrc hack ? (http://www.nvnews.net/vbulletin/showthread.php?t=95803)

elsewhere 07-30-07 10:33 PM

What is the PerfLevelSrc hack ?
 
I've seen reference to this before, in terms of matching up the modprobe.conf setting with the appropriate .ini file setting from Windows.

Can't find an explanation on what it does, though, but I gather it may be a "discouraged" workaround ?

Used it on my old laptop (an HP dv6000) with a GeForce 7200, and it eliminated some XID errors I was having with beryl. However, I also wound up frying the nvidia adapter in that system after about 5 months, although HP graciously replaced the motherboard under warranty. The sucker did get really hot while I was using it. I didn't do any other "tweaking" to the system.

That lappie wound up going to my gf while I'm now using a dv9000 with a lesser 6150 adapter, and I've found the reference in my Windows ini file to be 0x3333 for PerfLevelSrc. I'm having issues with Compiz (posted a previous thread about "WAIT" errors, though not the same as the XID errors I was having on the old one), is there a point in trying?

I guess what I'm wondering if anyone can shed some light on what particular setting is being tweaked with that option, and what the risk factor is? Could be my last laptop fried the nvidia adapter simply from overheating in general, or could it have been the tweak?

Inquiring minds want to know... ;)

Thanks in advance...

Cheers,
KV

shaundennie 08-02-07 05:40 PM

Re: What is the PerfLevelSrc hack ?
 
Although I don't actually know what its purpose is, one of the side effects of the tweak is that it causes your GPU to be at max speed at all times (rather than ramping up on demand). That causes the GPU to become much hotter and, if you are using a laptop with poor cooling/blocked air vents/dirty fans/non-functioning fans/etc, yes, it would certainly shorten the life of the laptop.

I recently did a massive cleaning on my laptop and the average idle temp while using compiz and the tweak dropped about 20C. If you use the hack, make sure to at least use some compressed air on your laptops vents fairly regularly (once a month should do it depending on the environment). It makes a huge difference.

mooninite 08-02-07 06:16 PM

Re: What is the PerfLevelSrc hack ?
 
Um... with such low performance chips I wouldn't bother tweaking. Just save up some cash and buy a new laptop with a faster chip.

It's unfortunate that laptop makers didn't widely adopt nVidia's own exchangeable chip design for laptops.

shaundennie 08-02-07 07:52 PM

Re: What is the PerfLevelSrc hack ?
 
Quote:

Originally Posted by mooninite
Um... with such low performance chips I wouldn't bother tweaking. Just save up some cash and buy a new laptop with a faster chip.

It's unfortunate that laptop makers didn't widely adopt nVidia's own exchangeable chip design for laptops.

I don't know what you mean by this. Any 5/6/7/8 series nvidia laptop card is more than capable of running a composited window manager. Surely the answer to, "Should I worry about my very capable hardware burning out?" isn't, "Buy more expensive hardware". He isn't even "tweaking". For many laptops, the PerfLevelSrc hack is actually needed to even get a composited desktop stable.

mooninite 08-02-07 09:36 PM

Re: What is the PerfLevelSrc hack ?
 
I've used Beryl/Compiz on low-end nVidia cards (5200, 7300) to high-end (7950+) and there is a tremendous difference.

Then again I'm using super hi-resolutions with two monitors and normally 10-20 apps running. That kills the low-end cards even on some 2D stuff.

However, even on a laptop Beryl will give those low-end cards a workout. I'll speak hypothetically and say that it is doing lots of up and down clocking, which maybe the driver is not 100% stable in doing it.

XID errors typically mean the driver received a hardware error. I normally see them when the cards are overheating or about to die (two have died when lots of XID errors started happening). Tweaking the driver to "reduce" XID errors is only delaying the inevitable.

Yes, he will have to buy better hardware. Why are you so cheap? Spend an extra $100 and get a chip that is twice as fast, won't overheat, and will last you a while.

shaundennie 08-02-07 10:08 PM

Re: What is the PerfLevelSrc hack ?
 
Quote:

Originally Posted by mooninite
However, even on a laptop Beryl will give those low-end cards a workout. I'll speak hypothetically and say that it is doing lots of up and down clocking, which maybe the driver is not 100% stable in doing it.

Yes, it is. And, no, the driver isn't always stable doing those frequency changes. That is in fact the way the PerfSrcLevel hack came into existence. The clock changes were causing machines to hang.

Quote:

Originally Posted by mooninite
XID errors typically mean the driver received a hardware error. I normally see them when the cards are overheating or about to die (two have died when lots of XID errors started happening). Tweaking the driver to "reduce" XID errors is only delaying the inevitable.

No, you are wrong. Even if XID errors were caused by heat, that does not imply that the heat problem is because you are taxing the capabilities of the video card. It could be a driver problem, BIOS problem, ventilation problem, etc.

Quote:

Originally Posted by mooninite
Yes, he will have to buy better hardware. Why are you so cheap? Spend an extra $100 and get a chip that is twice as fast, won't overheat, and will last you a while.

Why not try to get the performance that your card is obviously capable of without risking shortening it's lifespan? Having users throw money at a problem only allows vendors to continue to produce sub-par hardware and drivers. Buying a new card is the worst possible solution considering that his hardware is obviously capable of doing what he wants.

I also don't understand why you are calling me "cheap". A laptop is not a desktop. You can't just wander into a CompUSA and buy an upgrade for US$100. It's all or nothing. You buy a new laptop or live with what you have.

Thunderbird 08-03-07 04:26 AM

Re: What is the PerfLevelSrc hack ?
 
I think the hack corresponds to the performance levels which are defined in the bios of your videocard. Nvclock can for instance show them.

I'm not sure what the value itself means but I think each digit corresponds to one performance level (I guess there are standby, 2d, 3d, throttle or something like that). And then each digit corresponds to one performance level from the bios.


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