How much RAM can Pentium II Overdrive cache on 440FX socket8 motherboard?
The PII Overdrive has 512kb of on package cache running at full CPU speed so I doubt you need to worry about how much it can cache as it'll behave like every other CPU with on die cache. It can cache its full address space of 4Gb which you will never hit on a socket 8 board, the Over drive uses the PII Xeon Deschutes core so doesn't have the 512Mb limit the PII Klamath does.
So go ham but I doubt you will ever need more than 512Mb on a socket 8 board unless you intend to run a server with it.
red-ray wrote on 2025-06-08, 12:03:No, it's 64 GB ! […]
Trashbytes wrote on 2025-06-08, 10:51:It can cache its full address space of 4Gb
No, it's 64 GB !
sure sure, 64 Gb.
But for us normal people its 4gb, only mad men would try to put 64gb into a socket 8 board !
Also the cost of the EDO Simms would be eye watering, just getting 512MB wouldn't be cheap just looking at the prices on Evilbay.
My own setup only has 256MBb in it due to the cost of the sticks.
Trashbytes wrote on 2025-06-08, 12:10:But for us normal people its 4gb
Your post is pointless and incorrect, its 64 GB and this does not vary. It's also nothing to do with the core, it's all down to the L2 cache. It's also 64 GB for P-II + P-III Xeons.
Normal people? Here? 🥲
i386 16 ⇒ i486 DX4 100 ⇒ Pentium MMX 200 ⇒ Athlon Orion 700 | TB 1000 ⇒ AthlonXP 1700+ ⇒ Opteron 165 ⇒ Dual Opteron 856
PD2JK wrote on 2025-06-08, 12:33:Normal people? Here? 🥲
You do have a point . .i dont like it but its still valid !
red-ray wrote on 2025-06-08, 12:29:Trashbytes wrote on 2025-06-08, 12:10:But for us normal people its 4gb
Your post is pointless and incorrect, its 64 GB and this does not vary. It's also nothing to do with the core, it's all down to the L2 cache. It's also 64 GB for P-II + P-III Xeons.
Whats pointless is quoting details that have zero relevance to anyone wanting to have a reasonable usable amount of memory in their Over Drive PC, even 4Gb is pointless let alone stating 64GB and expecting anyone to take you seriously.
Except the PII Klamath .. that's limited, but you already know this right.
Now I remember why I quit responding to your posts.
Trashbytes wrote on 2025-06-08, 12:38:"pointless ramblings"
I simply corrected your error of saying the limit is 4GB when it's 64GB. All your posts after I did this are pointless and I am at a loss as to what you hope to achieve do doing this.
I feel you would be wise to check the facts before making incorrect posts.
Trashbytes wrote on 2025-06-08, 12:38:Now I remember why I quit responding to your posts.
Thank you, I never liked the incorrect information you tend to post without checking.
Interesting.
On internet I found info that:
"It can cache up to 4GB.
But it can adress up to 64GB."
So which is it? Is this internet info wrong? If it is wrong, why there is such info?
Also where does the border lie between Pentium IIs that can cache up to 512MB and the ones that can cache more?
Apparently not only Klamath but also some early Deschutes could cache only up to 512MB.
How can I easily check if my Pentium II 333Mhz can cache up to 512MB or more?
Apparently they need "82459AD L2 cache controller/tag RAM chip" to cache more than 512MB.
How to check if a Pentium II has this "82459AD L2 cache controller/tag RAM chip"?
3dfx_fan wrote on 2025-06-08, 13:27:Apparently not only Klamath but also some early Deschutes could cache only up to 512MB.
How can I easily check if my Pentium II 333Mhz can cache up to 512MB or more?
Interesting I have never come across a Deschutes with the 512MB limit, I guess maybe the early 66 MHz FSB ones have this limit
Update: I did some checking and suspect the ones with CPUID 0650 are the most likely ones to have a 512MB limit as at lest one CPUID 0651 has 4GB.
To check you need to look at what is in MSR 0x011E (BBL_CR_CTL3)
But for us normal people its 4gb, only mad men would try to put 64gb into a socket 8 board !
I'd do it, in a heartbeat. Granted it would be one of those 42U rack servers, but still. I think 64gb might be more of a academic limit than a practical one.
I'm planning on getting the last infinity stone for my ALR today. and I'll be testing it with 4gb of ram.
It is a mistake to think you can solve any major problems just with potatoes.
3dfx_fan wrote on 2025-06-08, 13:30:Apparently they need "82459AD L2 cache controller/tag RAM chip" to cache more than 512MB.
How to check if a Pentium II has this "82459AD L2 cache controller/tag RAM chip"?
Looking at the S-Specs on CPU World the TagRAM is listed as either T6P for 512MB or T6P-e for 4GB. I decided to add this information to the SIV table, thus far I have found only two that are T6P, there are 6 unknown and all the rest are T6P-e.
If you have one of the unknown please will you post the CPU S-Spec and what the cacheable range is please?
I just spotted that there is a CPUZ dump for the SL2TW so I used it to run SIV in test mode and it's 4GB.
The S-Spec says the SL2QF is 512MB
Intel ASCII Red Pentium Pro server had 594gb of ram (supposedly)
rmay635703 wrote on 2025-06-11, 15:15:Intel ASCII Red Pentium Pro server had 594gb of ram (supposedly)
That was in total, not per motherboard. It was also upgraded to Pentium II Overdrive
rmay635703 wrote on 2025-06-11, 15:15:Intel ASCII Red Pentium Pro server had 594gb of ram (supposedly)
Cool Stuff. Surprising relevant. I hope one shows up on a lawn near my house some day!
That Giant 1212GB RAM number probably sums up the ram from all nodes. Seems unlikely that the the overdrive CPU's cached ram that wasn't on their node. Probably only had 256MB RAM on each node.
https://en.wikipedia.org/wiki/ASCI_Red
Every one of the compute nodes accommodated two 200 MHz Pentium Pro processors, each with a 16 KB level-1 cache and a 256 KB level-2 cache, which were upgraded later to two 333 MHz Pentium II OverDrive processors, each with a 32 KB level-1 cache and a 512 KB level-2 cache. According to Intel, the ASCI Red Computer is also the first large scale supercomputer to be built entirely of common commercially available components.
