No need to send the manual, I had already downloaded it and checked before I said what I did above. You are wrong. There is no onboard cache on these boards. You have misunderstood the meaning of a BIOS setting and/or an entry in the manual. It is quite clear from diagrams and photographs of the boards that there are no cache memory modules onboard. The manuals do not mention onboard cache as a feature. The manuals do not mention how to operate this alleged onboard cache memory. It is possible you are confused by the terms 'CPU Internal cache' and 'External cache'. These are just other terms for Level1 cache and Level2 cache. Level1 cache is built into the body of the core processor circuit itself - it's internal. Level2 cache is external because it is outside of the processor circuit. With Slot1 CeleronAs, PIIs and some PIIIs, the external Level2 cache is contained in chips mounted on the little board that the core processor chip sits on (and runs at half the core frequency). With Socket370 PIIIs and some Slot1 PIIIs, the external Level2 cache is actually on the same piece of silicon as the core processor, but still external to the processor circuit (and runs at full core speed). If you disable the external cache via the BIOS, you are simply turning off the Level2 cache that comes with the PIII. This will slow the system right down. Turning it on again will speed things up back to normal. External cache is enabled by default. There are also various adjustable settings elsewhere in the BIOS for how the External cache is configured. In this section it is specifically refered to as L2 cache. It is also possible to cache the BIOS itself into system memory (RAM), which has the potential to speed things up. These are the most likely candidates that have caused your confusion. I don't mean to be offensive, but I there isn't a way to say you are wrong except to say that you are wrong.