First post, by jesolo
I've been playing around on old PC hardware for a couple of years now.
One thing that I haven't yet fully tested is the turbo switch functionality on these systems.
Please note, the purpose of this topic is not to discuss other methods of slowing down your system (like disabiling the L1 & L2 cache in the BIOS or using slow down utilities like ICD.EXE & ICE.EXE).
I currently have two 486 motherboards, one being an ASUS VL/I-486SV2GX4 motherboard and the other one an ASUS PVI-486SP3.
Both motherboards have an AMD 486DX4-100 NV8T (write-through L1 cache) CPU on board (I also tested the PVI-486SP3 motherboard with an Intel 486DX-33 CPU).
On both systems, the turbo switch (provided of course that it is connected properly to the motherboard) works perfectly and slows down the AMD 486DX4-100 to the speed of an Intel 486DX-33.
A couple of years ago I also owned a Gigabyte GA-5486AL motherboard with an AMD DX4-120 SV8B (write-back L1 cache) CPU on board.
On this particular system, pusing the turbo button did not have any affect on the speed of the CPU.
I also recall having tested the turbo switch functionality on some Pentium 1 boards (that did have the connectors for it) but, also no change in the CPU speed.
What I would like to establish is whether the turbo switch functionality is disabled on CPU's that has a write-back L1 cache scheme?
Or, is there another reason why this would not work on CPU's with write-back L1 cache schemes (maybe it's motherboard specific)?