Cache option in Hardware Menu? (Dumb Question)

Hi guys, I'm sure this is a really stupid question, but I'm a PC guy through and through, so go easy on me

I have a dual 1.42GHz MDD running Leopard, and I recently noticed in the Hardware menu under System Preferences, that the pulldown menus for L2 and L3 cache are set to "None" by default. If I set the L2 cache to 256KB, it stays until I close the window, and if I go back, it's set to "None" again. If I try to set the L3 cache to 2MB it immediately reverts to "None".

Is this just some dumb quirk of the menu, or is it actually disabling cache? The machine doesn't feel ridiculously slow like I imagine it would without L2 or L3 cache, but I also have no gauge for it, being the fastest Mac I've ever used. I do have Nap enabled if that's relevant.

Sorry if this is stupid, I'm new to OSX (and googling it is proving difficult since it just brings up spec lists)

Edit: I should add that About this Mac and System Profiler both report the correct amounts of cache.

Specs:
PowerMac MDD FW800
Dual 1.42GHz G4
2GB RAM
Radeon 9800Pro 128MB (flashed)
OSX 10.5.8 Leopard

Swampus said:

It doesn't report Level 2 or Level 3 cache correctly. The only thing that you want that for is to enable nap mode. It makes your CPUs run cooler without any hit to performance.

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Ok awesome, that's what I needed to know. Yeah, nap mode is sweet, it took my idle temp down from around 49C to about 34C, very cool stuff (haha). Thanks a lot, figured I was worrying myself over nothing.

Swampus said:

For a "PC guy through and through" you sure do have some interesting Macs listed in your signature.

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Hehe yeah, I like collecting and playing around with computer hardware, especially old stuff, and recently got on a Mac kick

The G3 B&W is kind of a funny story, actually. I had the Rage 128GL lying around because I'd bought it to use in a Voodoo2 SLI PC before discovering it was a Mac card. And the Voodoo2 I had spare because it's slightly faulty (it glitches up with some 2d textures, mostly HUDs, but otherwise works properly). After I got my MDDs I was browsing eBay and found a G3 for super cheap that was missing the video card. I threw my Rage128 in, installed OS 8.6, and put the mostly-working Voodoo2 in and installed the Mac drivers. It runs Diablo 2 in enhanced mode great! Also found out that the G3 had a Sonnet 450MHz G4 upgrade installed, so that was a bonus too

mayuka said:

Maybe a stupid question. Sorry for that. But how do I enable Nap on my PowerBook?

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Been a few months, but I think this is what I did to enable it (also I notice right there that it mentions the cache issue, so go me for not realizing that >< )

http://hints.macworld.com/article.php?story=20071101231643321