System Bios Cacheable

[Dr J]

Hello everyone.

I know that when system bios cacheable is enabled, within the bios of my mother board, the computer is faster, but seems less stable. What is actually happening in the two scenarios? If system bios cacheable is enabled, can it wear on or harm the curent bios and setup?

Any and all information appreciated.

thanks,

John

 

[Modelworks]

If that is enabled, one of the first things a bios does is copy itself into ram.
It may be less stable if some device or program attempts to use the same ram addresses that the bios was copied to.

It will not harm the current bios, since as soon as you reset the information in ram would be gone.

 

[Dr J]

Modelworks,

thanks for the explanation. It helps to know how these things actually work, than only knowing the effect.

If I understand you correctly, then, installing a higher quality, faster, more stable ram will not influence, then, in any way the system stability, with an enabled system bios cacheable?

Again, thanks.

John

 

[Peter]

Since about 1992, BIOS always copies itself to RAM, no matter the setting.

Before the operating system is even booted, the RAM where the runtime part of BIOS sits is getting write protected through CPU and chipset means.

Thus, there's no difference in stability. The system may be faster during POST and OS boot with BIOS cacheing enabled. Later, when the OS has booted all the way through, the BIOS isn't being called much anymore, so there shouldn't be any measurable difference in speed.

The rest is internet 'expert' mythology, very much like IRQ conflicts and stuff.

 

[Dr J]

I certainly can't provide the reason, but I notice a difference in the speed at which internet pages download and also in shifting windows/programs.

I had stability issues before and since installing a previous unified board driver, the system has been rock steady. However, before doing so, I turned off system bios cacheable, as a potential source of the problem. I'd like now to turn it back on and have, but wouldn't like it to crash and whack files, in the process.

I wish I could understand these computers more deeply.

Anyway, thanks for the response and explanation.

John

 

[Peter]

Well, this setting is often recommended, and people just as often think they see a difference - but it's snake oil. Really.

 

[Dr J]

I beg to differ. I had system bios cacheable turned on, for years. When I started with the stability issues, I turned it off and when I did, I noticed a slight decline in performance. Also, just today, I've turned it back on and again, see a difference, an improvement. I believe anyone would; but, I had nearly five years of it, turned on, compared to recently having had it turned off.

It's no big deal. My main concern is that it remain stable.

Thanks,

John

 

[JackMDS]

Internet pages speed is quite remotely in function from the BIOS.

Even if BIOS cashing helps, I doubt that it would be reflected in Internet Page Download.

I.e. you experience the Placebo effect.

 

[Peter]

J, you may beg to differ, but rest assured: Having something cacheable that isn't ever being called or used does not affect performance. Niente. Nada. Null. Nix.

 

[Dr J]

That's funny!

Does it influence the video card, in any way?

I'm telling you, I wish you could come here and see it for yourself; it's noticeable. I can't explain it as I don't know what the relation between hard and software is, but I know the effect.

Placebo? lol Well, I guess as long as I think it's better, then, that's all that matters; right?

thanks,

John

 

[Peter]

No it doesn't influence /anything/. All that BIOS setting does is set the memory range from 000F0000..00FFFFFF cacheable. That's where the runtime BIOS services reside - and these aren't ever being called once Windows has booted about halfway through.

You're seeing things that aren't there. Run a browser benchmark for a reality check.

 

[Dr J]

Peter,

I liked your previous comment better!

Thanks for the explanation, though. I'm not quite sure I understand why a board would have a feature that results in no effect, but, as I explained, my understanding of the whole thing isn't deep.

I wish you could come here and see for yourself.

John

 

[Peter]

The 'system BIOS cacheable' setting at least still does something ... even if it's pretty much pointless.

There is about half a dozen settings in some BIOSes (Award's, mostly) that don't actually do anything at all anymore - simply because the hardware they apply to has been obsoleted ages ago.

 

[Dr J]

Peter,

you're right, I believe mine is an Award bios.

I stand by my perceptions, however; it is smoother. I can't explain why, but there is an affect.

It doesn't matter. As I said, as long as it's not crashing, I'm happy.

Thanks,

John

 

[Steve]

Originally posted by: Peter
The 'system BIOS cacheable' setting at least still does something ... even if it's pretty much pointless.

There is about half a dozen settings in some BIOSes (Award's, mostly) that don't actually do anything at all anymore - simply because the hardware they apply to has been obsoleted ages ago.

I seem to recall a rather lengthy (yet enjoyable to read) argument between you and someone else here a couple of years ago. Though I don't believe it was the main point of the argument, you did answer a side point by mentioning the only setting with any real effect is (IIRC) Video RAM Cacheable. Is that still the status quo?

 

[Peter]

"Video RAM cacheable" does something relevant to Windows runtime ... if it manages to guess the exact memory location of the VRAM correctly. Given how VGA chips are completely free in how they implement their architecture (other than the legacy VGA compatible bits), getting this right for discrete graphics cards is always a bit questionable.

Many years ago, people have agreed that enabling any means of acceleration on the VGA memory should be left to the card's device driver - for it knows how its chip works. Be that cacheability, or just write combining, this is how it's done today, so we've got yet another sort of obsolete BIOS control.

Cacheing an I/O resource may have unwanted side effects anyhow. Bad idea.