How to tell is chip is Mcache

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

I have an ASUS P55T2P4 motherboard. It currently has 64 Mb Ram. I'd
like to increase it to at least 128 Mb. The manual says that in order
to do so so that the additional memory will be cached the onboard L2
chips need to be pipeline burst SRAM, not Mcache.

The chips are Winbond W25P012AF-7. Both the upgradeable TAG SRAM and
the L2 Upgrade Cache Expansion slots are empty.

How do I know if the existing on board cache is Mcache or burst SRAM?

If Mcache, the manual says that jumper J4 must be set to 64 Mb (and not
to 512) or it will be unstable.

If the onboard cache is Mcache am I really stuck at only being able to
cache 64 Mb of RAM?

I really want to increase the RAM to 128 Mb so I can run WindowsSE.
BTW, if I add a PCI/USB card to this motherboard will I be able to
access USB devices? The CPU is 200 MHz (WinChip CPU, but I'm not sure).
I've read that some USB cards need at least 233 MHz CPU's. I really
want to be able to access USB devices. This is the whole reason for
increasing the memory so I can use WinSE at a fairly decent pace. Or
would I be satisfied with it only running at 64 Mb. Any other gotcha's
I need to be aware of in this endeavor?

Thanks,
Bruce
7 answers Last reply
More about chip mcache
  1. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On 1 Mar 2005 01:58:01 -0800, b_egower@compuserve.com wrote:

    >I have an ASUS P55T2P4 motherboard. It currently has 64 Mb Ram. I'd
    >like to increase it to at least 128 Mb. The manual says that in order
    >to do so so that the additional memory will be cached the onboard L2
    >chips need to be pipeline burst SRAM, not Mcache.
    >
    >The chips are Winbond W25P012AF-7. Both the upgradeable TAG SRAM and
    >the L2 Upgrade Cache Expansion slots are empty.
    >
    >How do I know if the existing on board cache is Mcache or burst SRAM?

    IIRC, MCache was some bird-brained idea Intel had for the i430HX that mbrd
    makers could use fast DRAM chips instead of PBSRAMs. I'm not sure that
    Asus ever made a P55T2P4 with such a config... or anybody else for that
    matter. How much cache memory do have soldered to the mbrd? Check out the
    part nos to be sure but I'd be very surprised if it's not PBSRAM. The ones
    I bought all came with 512KB, i.e. two 256KB SRAMs soldered in, but if you
    have a COAST slot, I assume you have 256KB or 0KB??

    Assuming you have some SRAM soldered to the mbrd, to cache >64MB you need
    only to add a 16Kx8 <15ns SRAM for the TAGs. If there are no SRAMs
    soldered to the mbrd -- apparently Asus made such things though I never
    heard of, nor saw, them -- I think you're going to have trouble finding a
    COAST module to fit.

    >If Mcache, the manual says that jumper J4 must be set to 64 Mb (and not
    >to 512) or it will be unstable.
    >
    >If the onboard cache is Mcache am I really stuck at only being able to
    >cache 64 Mb of RAM?
    >
    >I really want to increase the RAM to 128 Mb so I can run WindowsSE.
    >BTW, if I add a PCI/USB card to this motherboard will I be able to
    >access USB devices? The CPU is 200 MHz (WinChip CPU, but I'm not sure).
    >I've read that some USB cards need at least 233 MHz CPU's. I really
    >want to be able to access USB devices. This is the whole reason for
    >increasing the memory so I can use WinSE at a fairly decent pace. Or
    >would I be satisfied with it only running at 64 Mb. Any other gotcha's
    >I need to be aware of in this endeavor?

    No idea on this but a recent PCI card may not work anyway due to PCI
    standards differences. Err, the P55T2P4 is just too old.

    --
    Rgds, George Macdonald
  2. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    George,

    Thanks for the quick reply.

    George Macdonald wrote:
    > On 1 Mar 2005 01:58:01 -0800, b_egower@compuserve.com wrote:
    >
    >
    > IIRC, MCache was some bird-brained idea Intel had for the i430HX that
    mbrd
    > makers could use fast DRAM chips instead of PBSRAMs. I'm not sure
    that
    > Asus ever made a P55T2P4 with such a config... or anybody else for
    that
    > matter. How much cache memory do have soldered to the mbrd? Check
    out the
    > part nos to be sure but I'd be very surprised if it's not PBSRAM.
    The ones
    > I bought all came with 512KB, i.e. two 256KB SRAMs soldered in, but
    if you
    > have a COAST slot, I assume you have 256KB or 0KB??
    >

    The COAST socket is empty so I am assuming I have 256KB since there are
    L2 onboard chips. But the manual has a very strong warning about not
    setting JP4 to 512 if there is Mcache onboard, so I would think that
    ASUS made at least some boards with Mcache. My board is Rev. 3.0.

    But how do I check out the part nos.? I've looked on the Internet for
    Winbond W25P012AF-7 and all I get are parts lists from various
    companies. No further info about what type of RAM it is, just a price
    or whether or not it is in stock.

    Bruce
  3. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On 1 Mar 2005 07:36:25 -0800, b_egower@compuserve.com wrote:

    >
    >George,
    >
    >Thanks for the quick reply.
    >
    >George Macdonald wrote:
    >> On 1 Mar 2005 01:58:01 -0800, b_egower@compuserve.com wrote:
    >>
    >>
    >> IIRC, MCache was some bird-brained idea Intel had for the i430HX that
    >mbrd
    >> makers could use fast DRAM chips instead of PBSRAMs. I'm not sure
    >that
    >> Asus ever made a P55T2P4 with such a config... or anybody else for
    >that
    >> matter. How much cache memory do have soldered to the mbrd? Check
    >out the
    >> part nos to be sure but I'd be very surprised if it's not PBSRAM.
    >The ones
    >> I bought all came with 512KB, i.e. two 256KB SRAMs soldered in, but
    >if you
    >> have a COAST slot, I assume you have 256KB or 0KB??
    >>
    >
    >The COAST socket is empty so I am assuming I have 256KB since there are
    >L2 onboard chips. But the manual has a very strong warning about not
    >setting JP4 to 512 if there is Mcache onboard, so I would think that
    >ASUS made at least some boards with Mcache. My board is Rev. 3.0.

    What was the original source of the mbrd? The only fools who would have
    had Asus build MCache boards would have been large OEMs trying to save a
    few cents. ISTR that the MCache never really worked right, with serious
    restrictions to do with timing issues... mentioned in the Data Sheets.

    >But how do I check out the part nos.? I've looked on the Internet for
    >Winbond W25P012AF-7 and all I get are parts lists from various
    >companies. No further info about what type of RAM it is, just a price
    >or whether or not it is in stock.

    The closest data sheet I can find is for a W25P022AF-7 which you can get
    starting here: http://www.dialelec.com/805.html. It's a 64Kx32 PBSRAM so
    I'd think it's safe to say your part is also PBSRAM and very likely 32Kx32
    - if you have two of them that'd make a total of 256KB of L2 cache, which
    also makes sense given the COAST socket to add a further 256KB.

    Though a 256KB COAST module would be nice, I think you'll have trouble
    finding one. You don't need 512KB of L2 cache to be able to cache >64MB of
    memory - the 256KB of L2 cache will also allow caching up to 512MB IFF you
    add a 16Kx8 or 32Kx8 TAG SRAM in the DIP socket. If you do find a COAST,
    make sure whether it has the extra TAG SRAM incorporated on the module,
    since you dont need the 16Kx8 in the DIP socket then.

    --
    Rgds, George Macdonald
  4. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    Thanks for the URL George.

    I think I'll go ahead and get a upgrade TAG SRAM. It can't cost that
    much. Nothing lost if it doesn't work. If it does, then my old P55T2P4
    will still be going strong after 8 years, especially if I can get it to
    work with USB (which the manual mentions can be enabled in the BIOS).

    Thanks for your help.

    Bruce
    George Macdonald wrote:
    > On 1 Mar 2005 07:36:25 -0800, b_egower@compuserve.com wrote:
    >
    > >
    > >George,
    > >
    > >Thanks for the quick reply.
    > >
    > >George Macdonald wrote:
    > >> On 1 Mar 2005 01:58:01 -0800, b_egower@compuserve.com wrote:
    > >>
    > >>
    > >> IIRC, MCache was some bird-brained idea Intel had for the i430HX
    that
    > >mbrd
    > >> makers could use fast DRAM chips instead of PBSRAMs. I'm not sure
    > >that
    > >> Asus ever made a P55T2P4 with such a config... or anybody else for
    > >that
    > >> matter. How much cache memory do have soldered to the mbrd?
    Check
    > >out the
    > >> part nos to be sure but I'd be very surprised if it's not PBSRAM.
    > >The ones
    > >> I bought all came with 512KB, i.e. two 256KB SRAMs soldered in,
    but
    > >if you
    > >> have a COAST slot, I assume you have 256KB or 0KB??
    > >>
    > >
    > >The COAST socket is empty so I am assuming I have 256KB since there
    are
    > >L2 onboard chips. But the manual has a very strong warning about not
    > >setting JP4 to 512 if there is Mcache onboard, so I would think that
    > >ASUS made at least some boards with Mcache. My board is Rev. 3.0.
    >
    > What was the original source of the mbrd? The only fools who would
    have
    > had Asus build MCache boards would have been large OEMs trying to
    save a
    > few cents. ISTR that the MCache never really worked right, with
    serious
    > restrictions to do with timing issues... mentioned in the Data
    Sheets.
    >
    > >But how do I check out the part nos.? I've looked on the Internet
    for
    > >Winbond W25P012AF-7 and all I get are parts lists from various
    > >companies. No further info about what type of RAM it is, just a
    price
    > >or whether or not it is in stock.
    >
    > The closest data sheet I can find is for a W25P022AF-7 which you can
    get
    > starting here: http://www.dialelec.com/805.html. It's a 64Kx32
    PBSRAM so
    > I'd think it's safe to say your part is also PBSRAM and very likely
    32Kx32
    > - if you have two of them that'd make a total of 256KB of L2 cache,
    which
    > also makes sense given the COAST socket to add a further 256KB.
    >
    > Though a 256KB COAST module would be nice, I think you'll have
    trouble
    > finding one. You don't need 512KB of L2 cache to be able to cache
    >64MB of
    > memory - the 256KB of L2 cache will also allow caching up to 512MB
    IFF you
    > add a 16Kx8 or 32Kx8 TAG SRAM in the DIP socket. If you do find a
    COAST,
    > make sure whether it has the extra TAG SRAM incorporated on the
    module,
    > since you dont need the 16Kx8 in the DIP socket then.
    >
    > --
    > Rgds, George Macdonald
  5. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On Wed, 02 Mar 2005 00:49:24 -0800, b_egower wrote:

    > Thanks for the URL George.
    >
    > I think I'll go ahead and get a upgrade TAG SRAM. It can't cost that
    > much. Nothing lost if it doesn't work. If it does, then my old P55T2P4
    > will still be going strong after 8 years, especially if I can get it to
    > work with USB (which the manual mentions can be enabled in the BIOS).

    Don't count on USB working. If you need it spend the $10-15 on a PCI USB2
    add-in card.

    --
    Keith
  6. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    On Wed, 02 Mar 2005 21:07:45 -0500, keith <krw@att.bizzzz> wrote:

    >On Wed, 02 Mar 2005 00:49:24 -0800, b_egower wrote:
    >
    >> Thanks for the URL George.
    >>
    >> I think I'll go ahead and get a upgrade TAG SRAM. It can't cost that
    >> much. Nothing lost if it doesn't work. If it does, then my old P55T2P4
    >> will still be going strong after 8 years, especially if I can get it to
    >> work with USB (which the manual mentions can be enabled in the BIOS).
    >
    >Don't count on USB working. If you need it spend the $10-15 on a PCI USB2
    >add-in card.

    I imagine any USB2 card is going to require at least a PCI 2.1 host, and I
    don't believe the 430HX met that minimum...
  7. Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

    I'll probably get an older, used USB card somewhere. Even if it is only
    1.1 I will at least be able to use some of my USB devices that are
    backwards compatible. If nothing else my pen drive will work with it
    and then I can at least change files with my Dell laptop which doesn't
    have a floppy. Anything else beyond that would be icing on the cake.

    Thanks for all the valuable insight from this group.

    Bruce
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