What is DRAM, SRAM and VRAM
Steve Alexandre
just a little question. What the difference between DRAM, SRAM and VRAM.
I remember DRAM is dynamic RAM so we have to refresh it but is it faster or
not than SRAM?
And what is the video RAM (VRAM)?
Why using it?
Thanks!
Stevee.
Stephan A. Maciej
> Hello,
>
> just a little question. What the difference between DRAM, SRAM and VRAM.
>
or
> not than SRAM?
I can't answer the question "is it faster or not". This basically depends
on the implementation of the circuit on the silicone dice......
Normally DRAMs are produced for size (large memories) while SRAM is
produced for speed (less memory but a higher access speed). This largely
depends on some etablished techniques in chip manufactoring: while
DRAM is physically organized as a matrix of single memory cells, SRAM is not
necessarily (this organisation technique has some access and refresh
advantages). The fastest SRAMs available have an access speed of 8ns while
the fastest affordable DRAMs have reached the 45ns line.
> And what is the video RAM (VRAM)?
> Why using it?
VRAM is just a DRAM with two access ports: you can access two
different memory locations at the same time. Normally the Video RAM
(that one located on your video adapter) is read out by the controller
logic and the data outputs are connected to a DAC. The read access goes
on and on, so there's in fact no time for the processor to access the
Video RAM. With VRAM, the processor uses the 2nd access port of the
RAM to perform read/write cycles while the DAC reads the memory contents
via port 1.
>
> Thanks!
>
> Stevee.
>
> sa...@imo.qc.ca
Stephan
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