VOGONS


First post, by .info

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I recently picked up a Compaq Presario 5240 (K6-2/400) and upgraded it with a K6-2+/570. One problem I am having is that the bios does not have a setting to disable the onboard cache which is acting as L3 with the K6-2+. This prevents slowing down the cpu below 486 speed with setmul. The chipset is VIA MVP3, I was hoping maybe a utility exists to disable the cache. I checked the motherboard and did not see any way to disable via a jumper or remove the cache chip(s). Any suggestions?

Reply 1 of 9, by Sphere478

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There may be a way with a pin mod. Tillamooks had a bad habit of breaking compatibility with l2 cache. If you could replicate that problem you may be able to disable it via pin mod.

Tillamook 266MHz and working L2 cache?

Also, try central tweaking unit. But I think that only controls cache on the processor.

Have you checked for a updated bios or checked the bios bin for locked/hidden settings?

There is a good chance that actually removing the cache with hot air would work. But that’s less than ideal for sure.

Speaking of, maybe a tillamook would be a better fit because of this exact problem?

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 2 of 9, by brian105

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BIOS is unfortunately a no-go: I have a very similar Presario and the BIOS is some non-standard Phoenix crap which should never have seen the light of day. No cache settings to be seen. There are a few settings hidden in the dumped BIOS when viewed with a hex editor, but I highly doubt they can be enabled.

Presario 5284: K6-2+ 550 ACZ @ 600 2v, 256MB PC133, GeForce4 MX 440SE 64MB, MVP3, Maxtor SATA/150 PCI card, 16GB Sandisk U100 SATA SSD
2007 Desktop: Athlon 64 X2 6000+, Asus M2v-MX SE, Foxconn 7950GT 512mb, 4GB DDR2 800, Audigy 2 ZS, WinME/XP

Reply 3 of 9, by .info

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I tried CTU, it does not have an option to disable L3. There a couple additional slow down settings which allowed me to get a bit slower that setmul, still in the range of a 486-33. I still would like a way to disable the L3, this is otherwise a pretty nice rig,

Reply 4 of 9, by Sphere478

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.info wrote on 2022-06-23, 01:31:

I tried CTU, it does not have an option to disable L3. There a couple additional slow down settings which allowed me to get a bit slower that setmul, still in the range of a 486-33. I still would like a way to disable the L3, this is otherwise a pretty nice rig,

If you buy a LIF socket and a interstitial socket you can interrupt a few different pins before they make it to the motherboard. I suspect you may be able to disable cache by interrupting brdy, brdyc, or ads, adsc there are also a few other pins of interest. Those were the pins of interest on the tillamook mods that re enabled cache on them. But I’d have to look up what was going on there again to be of more help. One sec, I’ll pull up the datasheet.

If we figure this out, I can incorporate it into the tweaker so it can be switched on and off

Alternatively you could unsolder these pins from a black pentium mmx one by one and record the results

Edit:

https://datasheet.octopart.com/PENTIUM-MMX-23 … eet-7279168.pdf

Start on page 15

The obvious pin is the cache pin but reading it I don’t think it works the way we want it to.

https://www.amd.com/system/files/TechDocs/23542a.pdf
Here is the 2+ data sheet

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 5 of 9, by Zeerex

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Recently had this issue with a packard bell SIS530 MB which I needed to disable the L3 so I could get faster FSB. What I do was find out what type of BIOS (award / ami / phoenix) - it was an AMI bios - then found a thread here on Vogons with a ton of old versions of AMIBCP for which one of them worked! Was able to find, enable the setting and flash it to the mobo to turn off L3.

Reply 6 of 9, by Gmlb256

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.info wrote on 2022-06-23, 01:31:

I tried CTU, it does not have an option to disable L3. There a couple additional slow down settings which allowed me to get a bit slower that setmul, still in the range of a 486-33. I still would like a way to disable the L3, this is otherwise a pretty nice rig,

CTU can only tweak the K6-2/III(+) CPU and does nothing for the motherboard cache (L3 cache in your case).

VIA C3 Nehemiah 1.2A @ 1.46 GHz | ASUS P2-99 | 256 MB PC133 SDRAM | GeForce3 Ti 200 64 MB | Voodoo2 12 MB | SBLive! | AWE64 | SBPro2 | GUS

Reply 7 of 9, by Sphere478

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Zeerex wrote on 2022-06-23, 02:20:

Recently had this issue with a packard bell SIS530 MB which I needed to disable the L3 so I could get faster FSB. What I do was find out what type of BIOS (award / ami / phoenix) - it was an AMI bios - then found a thread here on Vogons with a ton of old versions of AMIBCP for which one of them worked! Was able to find, enable the setting and flash it to the mobo to turn off L3.

OP should definitely try this suggestion. It’s a perfect solution.

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 8 of 9, by .info

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Well, I will have to learn a bit about how to mod this type of bios (or any bios for that matter), but it does sound like the proper solution. Thanks for the suggestion. If anyone knows of some good information that I could study to figure out how to do this, I would appreciate that.