Cache size?

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startmenu
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Cache size?

Post by startmenu » Sun 13 Sep, 2015 5:25 am

The CPU cache size options are "a little", "a bit", "some", "a lot" and "infinite" instead of a exact size like "8K" or "16K".
What are the exact sizes of those options? Are the sizes different on different machines?

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SarahWalker
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Re: Cache size?

Post by SarahWalker » Sun 13 Sep, 2015 7:00 am

There are no exact sizes, as it's a fairly crap simulation. I keep thinking of taking it out, but people seem to keep using it.

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ppgrainbow
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Re: Cache size?

Post by ppgrainbow » Sun 13 Sep, 2015 2:10 pm

startmenu wrote:The CPU cache size options are "a little", "a bit", "some", "a lot" and "infinite" instead of a exact size like "8K" or "16K".
What are the exact sizes of those options? Are the sizes different on different machines?
On the AMI486-based machine, the AMI system configuration reports 64 KB cache memory and on the AMI WinBIOS 486-based machine, 256 KB cache memory is reported. Options such as "16 KB", "32 KB", "64 KB", "128 KB" and "256 KB" cache size options would be implemented.

Tom, I'm wondering if there is a way to adjust the size of the cache RAM if it is implemented. The advanced CMOS setup options have the ability to enable or disable internal and external cache options. If the cache size options are taken out, I'm thinking about disabling the cache completely in the BIOS.

SA1988
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Re: Cache size?

Post by SA1988 » Sun 13 Sep, 2015 2:58 pm

TomWalker wrote:There are no exact sizes, as it's a fairly crap simulation. I keep thinking of taking it out, but people seem to keep using it.
Well, using Cache size set to "A little" helps a lot.

Battler
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Re: Cache size?

Post by Battler » Sun 13 Sep, 2015 3:09 pm

Yeah, the emulator is the fastest when the cache size is set to "a little".

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SarahWalker
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Re: Cache size?

Post by SarahWalker » Sun 13 Sep, 2015 3:44 pm

Yes, it helps by making the emulated processor much much slower. It's a pretty dismal simulation of a bad memory system.

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leilei
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Re: Cache size?

Post by leilei » Mon 14 Sep, 2015 5:05 am

I only use the "a lot" setting for Pentiums since infinite is quite a bit chokey on AMD. and I use "a little" on the faster 486s to get more of that m919 feel.

If the cache system is a progress/performance bottleneck I wouldn't mind it gone, i'll just use lower clocked CPUs instead.

ecksemmess
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Re: Cache size?

Post by ecksemmess » Mon 14 Sep, 2015 7:35 am

Granted that the cache simulation feature obviously has its shortcomings, I've found it incredibly useful as an auxiliary speed- and performance-tweaking feature when the main settings on their own aren't quite allowing me to get the emulated system to behave the way I want it to. I've spoken to several mates who use PCem, and all have agreed on this; we all use the cache setting quite a bit for that purpose. I would say that, if there is ultimately some need to remove or disable the cache setting, it should at least be possible to re-enable it in some sub-menu somewhere, as many of us have come to be somewhat dependent on it. If the issue is just a worry about misrepresenting the feature as offering accurate cache emulation when it actually doesn't, that could be addressed easily enough by simply re-naming it to something vague like "execution delay simulation", or some such.

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