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I am thinking of getting a Dell X11 netbook, and it can go up to 8GB of DRAM, together with a 256GB Solid State Drive.

So in that case, it can handle quite a bit of Virtual PC running Linux, and Win XP, etc.

But is the 8GB of RAM not so important any more? Won't 2GB or 4GB be quite good if a Solid State Drive is used? I think the most worrying thing is that the memory is not enough and the less often used data is swapped to the pagefile on hard disk and it will become really slow, but with an SSD drive, the problem is a lot less of a concern?

Is there a comparison as to, if DRAM speed is n, then SSD drive speed is how many n and hard disk speed is how many n just as a ball park comparison?

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3 Answers 3

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RAM chips are much faster then a SSD.

Much faster.

I don't have any hard and fast numbers, but I believe that the max read time for a standard spinning hard disk is something like 50 GB / sec, SSD is 300 GB / sec, RAM is pretty much instant.

Scratch that and read the wikipedia article on SSD's. Some interesting numbers and comparisions.

One thing to note though is that as CPU speeds increase, memory speeds are not increasing as fast. This is projected to be the next big "bottleneck" in terms of computer speed.

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    CPU speed is not increasing that fast any more either... I had a 3.2GHz machine... but now just a Quad core 2.x GHz... If I run a single program then it can be actually slower. May 24, 2010 at 3:09
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    @Jian Lin, thats not correct, clock speed isn't everything. Just because you had a p4 that clocked at 3.2 ghz, doesn't mean its faster than your Core architecture CPU clocked at 2.XGhz, even at a single task.
    – micmcg
    May 24, 2010 at 4:15
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    The Core i7 does about 2x as much "processing" as a P4 per clock (for "normal" workloads, some things are much faster, others are the same on both.).
    – Chris S
    May 24, 2010 at 13:25
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DRAM is much faster than SSD's Flash memory. DRAM can be written to in smaller sizes (typically 32, 64 or 128 bits) where as SSD's have a block size of 4 to 128 KBytes. A SSD's block needs to be erased before it can be reused. All in all SSDs will be slower than DRAM, so there will always be a need for DRAM.

The same analogy can be made for CPU cache vs DRAM, which is why CPU's cache size are constantly increasing.

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if you are running virtual machines, you'll want as much ram as you can get. just because your hard drive is an SSD doesn't reduce the ram requirements. that just means that your battery life will improve, programs will open faster due to quicker read/write times, and your system will run quieter.

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