RAM Types (Advice Needed!)

Hi again!

I am trying to decide the best RAM for a new Aopen motherboard. My previous question to this forum has led me to decide on using two or four 128 MB DIMMs (thanks everyone!). Now I need to fully understand the nitty gritty details with the assorted RAM types. Here is some information paraphrased from the Aopen manual:

"...This motherboard has four 168-pin DIMM sockets that allow you to install PC-100 or PC-133 memory up to 2.0 GB (or 1.5 GB when using FSB=133 MHz). The motherboard supports SDRAM, VCM and Registered DRAM. The driving capability of new generation chipset is limited due to the lack of a memory buffer (to improve performance). This makes DRAM chip count an important factor to take into consideration when you install DIMMs. Unfortunately, there is no way that the BIOS can identify the correct chip count, you need to calculate the chip count by yourself. The simple rule is: by visual inspection use only DIMMs which are less than 16 chips. DIMMs can be single or double sided. They have 64 bits data and 2 or 4 clock signals. We strongly recommend choosing 4-clock SDRAM for its reliability..."

And then it goes on to describe how to visually identify 2/4 clock and single/double sided DIMMs. Now, my understanding is that ECC RAM utilizes higher chip counts (18?) and latencies so I will first rule out using ECC. These questions should really help me understand the RAM situation for this motherboard:

1) What exactly is the 2 versus 4 clock thing?

2) How should 'single' and 'double' sided DIMMs factor into my decision making?

3) Is registered DRAM favorably comparable to SDRAM?

4) Is VCM really a bad buy considering price, performance and future compatibility?

5) Why do you suppose this manufacturer would strongly recommend using DIMMS with less than 16 chips?

6) Why do you suppose this manufacturer would strongly recommend using 4-clock SDRAM?

Finally, the motherboard does use 4-way interleaving. It also has PCI clock multipliers of x2, x3, and x4 for the final RAM speed. Consequently, the RAM can be clocked anywhere from 66 MHz up to 155 MHz dependent upon the FSB/PCI settings. Perhaps you overclockers can help with these:

7) Would PC-150 CAS-2 128 MB DIMMs be the optimum choice for performance and reliability?

8) Considering all these 'official' specs, what would you buy and what would you look out for when dealing with Mushkin or Crucial?

Any other helpful advice or tips would be greatly appreciated!

Thanks again! Sarah McIntyre
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More about types advice needed
  1. OK, let me make this simple - go to www.crucial.com and look up your motherboard. They will list what is compatible with it. They also explain this technical stuff better then I can. You probably want (at least) 128MB PC133 CAS2 SDRAM.
    150Mhz RAM is for overclocking, so if you don't plan on overclocking, don't waste the extra money on it. I think you mean CAS2 vs CAS3 when you mentioned the clock 2 vs 4 thing, CAS2 is slightly faster but may have compatibilty issues on some MBs. ECC, registered and buffered RAM AFAIK are all mainly for servers.
    Hope this helps.
  2. Yeah- your best bet is to buy some CAS2 RAM from Crucial.com and you'll be fine. If the board supports RAM speeds up to 150mhz- go with the Kingston PC-150 RAM. RAM is the bottleneck in any system... The CPU is always going to benefit from faster memory and so will overall system performance.

    -MP Jesse
  3. Ahh go with Crucial 128 (don't get 256's that is where "I bleleive" where they are talking about chip counts, # of chips on board adn they can be on 1 or both sides).

    Now there is Cas 2 and 3 the 2 and 4 bit they are talking I am sorry to say I can not help you out with. Just pointing out because I think the prev. guy was wrong there. The Cas 2 has a lower latency (wait) than the 3 and is about 5-10% faster.

    As far as bottle necks if your a gamer the real bottlenesk is teh graphics card. Even with the Ultra. CPU's are far advanced of the GPU's.

    <b> Fragg at will!!! </b>
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