mixing ram

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  #1  
Old 11-10-02, 08:01 AM
Q
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mixing ram

Are you allowed to mix PC100 and PC133 RAM?
I know you are not allowed to mix SIMMS and DIMMS.
Also how can you tell what bus speed your ram is?
 
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Old 11-10-02, 03:34 PM
bluecanary25
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From what I have read and experienced;
Should be able to mix PC100 and PC133 RAM.
BUT!!!!!!!...... They will run at the slowest speed = PC100.
Dont' mix them any-which-way, group the PC 133s together.
Cheap as RAM is, recommend using same speed DIMMs.
For most users, RAM speed will not make much difference.
If application launches 40 microseconds faster, who's gonna notice?
 
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Old 11-10-02, 05:54 PM
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So you are saying that it's ok to mix them.

I have two slots for RAM total. How do I find out what bus speed one of them is running at?

Also I want to purchase 256MB RAM DIMM PC133 that says something like "32X64". What does that mean?
 
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Old 11-10-02, 07:22 PM
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The owners manual for the motherboard will tell you how much and what kind of ram to use as well as the bus speed of the board. Ram chips are usually marked as to the speed, e. g., PC 100, PC 133
 
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Old 11-10-02, 08:42 PM
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Your BIOS will probably let you set the processor and RAM speeds. If not, your MB will have jumpers for it (see the manual.)

The key thing is that you must run the RAM at 100mhz. If will just freeze up if you run it at 133 with 100mhz RAM in it.

Check what the MB manual says about mixing RAM, it will have guidelines. Follow them carefully! You are asking for it to go against the manual on RAM recommendations.

If it says nothing, then go ahead and stick them anywhere. The newer MBs are pretty smart about figuring out what is where. But you still have to make sure it runs at the slower speed.
 
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Old 11-10-02, 10:20 PM
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Here are some things my motherboard guide says:

(((((((((
-SDRAM may be 83MHz, 100MHz, 125Mhz, or 133MHz bus ram
-SDRAM supports 32, 64, 128, 256, 512MB DIMM Modules
-We recommend to use PC100/VC100 Memory module for bus speed 100MHz and PC133/VC133 Memory for bus speed over 100MHz.
)))))))))

In the front of the guide it says:

"An AMD Socket A Processor based mainboard (100MHz)
Supports PC133/VC133 Memory Modules"

So is my bus speed 100MHz? Im confused because it says 100MHz, but then why does it support PC133? Or are they separate things?
 
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Old 11-11-02, 04:54 PM
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Also the ram Iwant to purchase says "32 x 64" what does that mean?
 
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Old 11-11-02, 05:57 PM
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Sorry, I should have answered that in my first reply. I'm pretty sure that 32x64 just means that the DIMM is using 32 bit memory (aligned in proper double words instead of bytes) times 64M, meaning you have 256MB (4 bytes times 64 mega-units.)

Something like that anyway. It's not really relevant.

So ... your main board sounds like it's very smart about memory. You stick your old memory in and your new memory and you tell the main board (CMOS or jumpers as per the manual) what your chosen memory bus speed is. Right now, if you have PC-100 memory installed, I'd bet that the machine is set to use a memory bus speed of 100mhz.

You'll want to just leave it alone after you've added the new memory stick. It should work fine. I've mixed 100/133 in several machines and had no problems running at 100mhz.

Good luck.
 
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Old 11-11-02, 06:04 PM
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One more thing ... about the PC133/VC133 --

From a couple of WEB pages:

VCM SDRAM
Virtual-Channel Memory SDRAM
(V-C-M-S-D-ram)

A variation of SDRAM with 16 channels of independent cache lines. VCM has fewer page misses due to the cache and typically requires less power.

VCM
(Virtual Channel Memory)
VCM is a memory architecture being developed by NEC. It allows different "blocks" of memory to interface separately with the controller, each with its own buffer. This way, different system tasks can be assigned their own virtual channels. Information related to one function does not share buffer space with other tasks being completed at the same time, making overall operations much more efficient.

Basically, it looks like there is a new SDRAM in town. Just in time to get killed by DDR RAM I suppose :-).

Your MB supports both. Since you've got one stick of SDRAM, just keep using it. The difference moving to VC133 will be pretty minor.
 
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