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Problems installing Windows 95 with DIMM

leodaza asked
Medium Priority
Last Modified: 2013-12-16
I need help, my computer is a Pentium MMX - 233, function perfectly with a SIMM memory (2 banks of 8M, 16 total), I buy a 32 DIMM memory but when try install Windows 95 OSR2, the installation finish and restart the computer, in the screen blue, appear many errors with OE, VMM and VCACHE, but installing the old memory all function perfectly, already try formating all the hard drive, change the memory, change the motherboard, change the voltage of the DIMM. The memory function perfectly in another computer, and when return the old memory (SIMM) every return to normality..???
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how do you use your memory modules ?
Do you mix them (SIMM+DIMM) or do you replace your SIMMs with your DIMMs ?

Please check your manual if it supports mixed memory modules.
Let me know, so we can proceed.

Best regards

It is NEVER advisable mixing DIMM and SIMM Memory!
Even if the board may have support for doing so, DON'T.


you're right, but in some cases it would be cheaper to combine them instead of throwing away the SIMMs and replace them with DIMMs.


it's important to know that your machine will use the slower SIMM timing for SIMMs AND DIMMs regardless how fast your DIMMs will be. That means the best timing for your DIMM wil be 60ns when you mix them (instead of possible 10ns).
As I said:
Please check your manual if mixed mode is supported.
In any other case (if it's not a money problem) try to use only 1 module type.


Simms and dimms are do not use the same voltage, if you mix them you will most likely damage one or the other.  Besides the fact that they different speeds and can cause problems.

It sounds like you need to sort out memory timings in the BIOS. Some memory/motherboard combinations make these settings ABSOLUTELY CRITICAL!

Experiment with these and I'm sure that eventually you will find the setting that suits your board/memory

There is a difference in the operating voltage for certain types of DIMMs. (EDO or SDRAM)
Some motherboards can not use both types.  Others may need jumpers configured for their use.
What type of DIMM are you using?

Leodaza, look at the documentation for your motherboard and ensure that it is setup to use a single 32 MB DIMM.  Many motherboards will only accept RAM in pairs.  Your motherboard documentation should say what types of memory configurations are possible.  Good Luck.


Thanks, but.
My motherboard is a Tx-pro II, in the manual says that support both types of memory, but i try with only DIMM, the jumper setting is 3.3 V, i do the next test, I has installed the windows 95 with SIMM, retire the SIMM and install the DIMM, when try enter newly to Windows return the errors. Could i test the memory en only system symbol?, i no had information of the my DIMM memory.. Please help...
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Very thanks smeebud,
The test of the first 16MB, the computer function ok, could test the next 16?, i try with 13FF (20 MB), and then return to anormality, the number is rigth o the memory is damaged?, do you know a program that test correctly the memory, could test memory intervals?, and the memory has been changed two times, is possible that the motherboard (that too has been changed), cause physical damage? How do to know the voltage of the memory?, in the chip no say information and no have documentation.

Check out
Utilities Everyone Should Have
Many Diagnostic Programs


Better idea:
This article describes how to locate adapter RAM and ROM addresses in the upper
  memory area (UMA) by using the Microsoft Diagnostic (MSD) utility and/or excluding
  memory ranges on the EMM386.EXE line in the CONFIG.SYS file.

  The UMA, which is between 640K and 1024K, is primarily reserved for RAM and ROM on
  hardware devices. The UMA is also used by EMM386.EXE to load device drivers and
  terminate-and-stay-resident (TSR) programs into available addresses in the UMA.
  Conflicts can result when either of the following occur:

  * Two or more hardware devices are trying to use the same memory address in the UMA.

  * EMM386.EXE is unable to detect whether an address is in use by a hardware device
  and loads a TSR program or device driver into that address.

  To determine which of the above is causing the problem, edit your EMM386.EXE line in
  the CONFIG.SYS file to read as follows:
  device=c:\dos\emm386.exe noems x=a000-f7ff
  Reboot the computer. If the problem still occurs, it may be caused by multiple hardware
  devices using the same memory address. In such cases, you must consult your
  hardware documentation or manufacturer for information on resolving the conflict.
  If the problem does not occur, it is most likely being caused by a conflict with
  EMM386.EXE and a hardware device in the UMA. To resolve this type of conflict, you
  must identify which upper memory addresses are being used by hardware and then
  exclude these addresses using the EMM386.EXE device line in the CONFIG.SYS file.
  The Microsoft Diagnostic (MSD) utility can be used to identify upper memory blocks
  (UMBs) in use by hardware. To do this:

  1. Reboot the computer and perform a "clean boot" by pressing F5 once when the
  message "Starting MS-DOS..." appears.

  2. Type "msd" (without the quotation marks) at the MS-DOS command prompt, and
  press M to select Memory. Using the legend at the top of the screen, locate the area(s)
  marked as RAM and/or ROM, and make a note of the starting and ending addresses of
  this area(s). This is the area(s) that needs to be excluded using the EMM386.EXE device
  line in the CONFIG.SYS file.

  3. Open the CONFIG.SYS file and add the exclusion(s) to the EMM386.EXE line (for
  example, X=C000-C7FF X=D800-DBFF), and restart the computer.

  If memory conflicts exist after you complete the above procedure, there may be some
  adapter RAM and/or ROM addresses that MSD is unable to correctly detect. Use the
  following technique to help isolate the conflicting memory region.

  1. Verify that the problem is being caused by a conflict in the UMA by editing the
  CONFIG.SYS file and specifying the following parameters on the EMM386.EXE device

  a. NOEMS b. X=A000-F7FF c. Remove any other X= or I= parameters d. Remove the
  HIGHSCAN parameter, if present

  A sample line might read as follows:
  device=c:\dos\emm386.exe noems x=a000-f7ff

  2. Save the changes and restart the computer. If the problem goes away, continue with
  the steps below. If the problem still occurs, it is not being caused by a conflict in the
  UMA, and you need to perform other troubleshooting to determine the cause of the
  problem. For more information on troubleshooting EMM386.EXE, query on the following
  words in the Microsoft Knowledge Base:
  emm386.exe and troubleshooting and notr

  3. If the problem is corrected by using X=A000-F7FF, edit the CONFIG.SYS file and
  shrink the excluded range by changing the parameter to X=C000-F7FF. Save the file and
  restart the computer. If the problem does not recur, proceed to the next step.

  If the problem does recur, the conflict may be in either the A000 or B000 range. To verify
  this, change the X=C000-F7FF parameter to X=A000-BFFF and restart the computer. If
  this corrects the problem, you can further narrow the range by changing the parameter to
  X=A000-AFFF. If the problem still exists, try X=B000-BFFF. Once you have narrowed the
  problem down to a specific range (B000-BFFF), you may be able to narrow it down to half
  of the range. To do this, try excluding either the first half (X=B000-B7FF) or the second
  half (X=B800-BFFF) of the range. If neither of these work, you must leave the whole range
  excluded (X=B000-BFFF).

  4. If specifying X=C000-F7FF does not cause the problem to recur, open the
  CONFIG.SYS file and shrink the range further to X=D000-F7FF. Restart the computer
  and see if the problem recurs. If not, shrink the range further to X=E000-F7FF. Repeat
  this process until the problem recurs.

  5. When the problem recurs, edit the CONFIG.SYS file to change the first number in the
  range back to what it had been and decrease the second number in the range. For
  example, if X=D000-F7FF worked correctly, but X=E000-F7FF did not, change the first
  number back to D000 and decrease the second number, so the range reads
  X=D000-EFFF. If that works, decrease the second number again (X=D000-DFFF). Once
  you have narrowed the problem down to a specific range (for example, D000-DFFF), you
  may be able to narrow it down to half of the range. To do this, try excluding either the first
  half (X=D000-D7FF) or the second half (X=D800-DFFF). If neither of these work, you must
  leave the whole range excluded (X=D000-DFFF).

  * If you have several hardware devices in your system using upper memory addresses,
  you may need to exclude more than one range. For example, you might list
  X=C000-C7FF X=E000-EFFF on the EMM386.EXE line.
  * If may be possible to narrow an exclusion to a smaller portion of a range (for example,
  X=C000-C3FF or X=C400-C7FF or X=C800-CBFF or X=CC00-CFFF.)

  The MSD utility contains a memory map that may be helpful in understanding how the
  upper memory ranges are divided and defined. To view the memory map, type "msd"
  (without the quotation marks) at an MS-DOS command prompt and then choose M for


Do you still have the problem?
We need some feedback from you.


Yes, i do, my problem continues, after trying the previus procedure, the problem is that multiple devices are using the same memory address, then why with the SIMM memory, i dont have problems? It could be incompatibility with some DIMM modules and Motherboard, or with Windows?


just to be sure:
Am I right that you have the device conflicts only when using DIMMs ?
Do these problems dissapear when using SIMMs ?

(hope I haven't misunderstood your comment from July18th; 9:11)


IOf that's true it sounds like you've got some bad DIMM.
You are not trying to use bothe simm and dimm are you??


Or, incorrectly configured motherboard........

Since you said: "memory has been changed two times", I still think the problem might be motherboard configuration. (If the M/B is supposed to use DIMM RAM.)

What is the make/model number of the motherboard?
If you don't know it, maybe we can find some info about it on the net.

Post the BIOS revision numbers displayed at the bottom of the screen when you start the computer. (Press pause key after the memory counts up for time to read it)



Thank's  for everybody, but the problem finally has solution, i change again the DIMM, and surprise the computer function ok.!!!
My memory was damaged in the two ocasions, but the memory was tested in the store (in other motherboard (tx-pro too)) and result ok.(?). Due to this the memory was change again.

Finally if my motherboard support both types of memory but not is recomended, that so dangerous coud be? Do you recomend that mixed the memory?


it makes sense not to mix both types of RAM.
In case your m/board supports both types, you're able to change voltage for your DIMMs (SIMMs and DIMMs usually run with diferent voltages).

The problem is another:
SIMMs usually "run" at 70ns / 60ns, DIMMs at 10ns / 7ns.
If you mix them, you're board will use the lower 60ns (unfortunately the DIMMs will run at 60ns, too !)...so you'll gain nothing...

Finally, many users experienced that mixing both types results in unreliable systems.


I have to echo Stavi. It's a Bad thing to mix the two even if your manual says it's alright.

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