Anand Keathley <[EMAIL PROTECTED]> asks: > Apple says that the G5s need no L3 cache because of the speed of its >Bus which is usually 1GHz. I'm running an AGP (Sawtooth) with a bus >speed of 100MHz so I would guess that having an L3 cache would be a >good idea. However I also would guess it would depend on the >application or multiple applications. Also, I believe it depends on >the cpu speeds available. The fastest G4 with an L3 cache is 1.5GHz >whereas ones without a cache are available to 2GHz. So, how much >faster would a no L# cache cpu have to be to match the speed and a cpu >with an L3 cache?
As you say, any speed boost largely depends on the app you're using. I can offer up my experience with one CPU-intensive benchmark to vouch for the value of an L3 cache. Quoting myself from my dual-CPU-heatsink-fabrication page: <http://mywebpages.comcast.net/macdan/dualG4_sink.html> "My original cpu lacks an L3 cache, and since the dually has 2MB L3s that alone makes a significant difference. My initial Q3A(G4) tests showed an immediate boost to the timedemo framerates (res=1280x, everything maxed), from ~62fps single cpu went to ~74fps with the dual." At the time of that test, I hadn't yet discovered how to enable a second CPU in Q3A, so the above framerates directly compare a single 800MHz without L3 (OCed L3-cacheless 733) to a single 800MHz CPU with L3. When I discovered how to engage the second CPU the rate jumped to ~110fps. (To test the value of the upgrade, save for the CPU swap all settings/HW/OS/etc. remained the same throughout.) So I reckon in this case the L3 alone added perhaps a 15%+ speedboost. In theory, that'd make an L3-less 933 roughly equal to an L3-equipped 800, or an L3-less 1.75GHz ~= to a 1.5 with L3. But as we know, the actual speedboost largely depends on the app, so YMMV quite widely. For me the biggest boost came of course from dual CPUs, which if you can afford 'em is definitely the way to go. With totally CPU-dependant apps (eg: Handbrake), the difference between single and dual can be nearly double. I'd take a dual 1GHz over a 1.5GHz single anyday. hth, dan k -- ................................. http://macdan.n3.net/ carracho://dankephoto.dhs.org:9700 hotline://dankephoto.dhs.org:9500 ................................. -- G-List is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- We have Apple Refurbished Monitors in stock! | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> G-List list info: <http://lowendmac.com/lists/g-list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:g-list@mail.maclaunch.com> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/g-list%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
