EMS HSDRAM : Tomorrow's Memory Today?
If you are reading this
article, you probably already know that SDRAM is the type of high speed memory
used in almost all PCs shipping today. However, you might be wondering what
the next big thing will be, or what the best is available today.
By now, you have probably
figured out that HSDRAM is just a synonym for high-performance SDRAM. What
justifies an H in the name? An HSDRAM chip must have low latency. That means
that it basically has a low hesitation factor when asked to remember something,
to put it into simple terms. Latency factor is determined by access time,
measured in nanoseconds (a billionth of a second, and abbreviated as ns).
With computer systems accessing memory at extremely high rates, a lower latency
can give a performance edge.
Enhanced
Memory Systems was kind enough to send me a PC133 HSDRAM for review. When
I received the chip, I was really impressed with it physically. It looked
almost too good to go into my computer, as it seemed like something meant
for a workstation or a server. The physical size was impressive, but for some
people, this might be a drawback if they have a cramped system or a large
heatsink. The chip is also made of high-quality, 6-layer PCB, and more layers
can increase stability of both memory chips and motherboards.
Specificaitons
|
- Industry
Standard PC133 SDRAM DIMM
- Fast
4.6 ns Clock Access Time
- Lower
Latency Than Other PC-133 Modules (3:2:2) @ 133 MHz
- CAS
Latency = 3
- RAS
to CAS Delay = 2
- Precharge
delay = 2
- High
Quality 6-Layer PCB for System Stability
- Uses
64Mbit Enhanced Memory Systems Chips for Consistent Performance
- Overclock
Existing PC Systems to 133 MHz
- Ideal
for High Performance 133 MHz Bus Speed Systems
- On-board
Serial Presence Detect (SPD
|
If you are looking
for some performance details, I found it best to just provide their latency
information. My running benchmarks against standard PC133 memory yielded inconclusive
results, so it became obvious that I would be unable to point out any differences
with my own numbers since my hardware is not capable of creating a performance
difference.
The
table below summarizes the results of several independent evaluations on
various Intel BX system boards. Each frequency is associated with the programmed
CAS latency and the number of modules installed to achieve successful operation.
A fast
access time of 4.6 ns provides the timing margins required to achieve these
operating frequency and system loading (number of DIMMs installed) statistics.
Operating
Frequency
|
CAS
Latency
|
64MB
DIMMs
Installed
|
128MB
DIMMs
Installed
|
150
|
3
|
2
|
2
|
143
|
3
|
2
|
2
|
138
|
3
|
3
|
2
|
133
|
3
|
4
|
3
|
133
|
2
|
2
|
2
|
125
|
2
|
3
|
2
|
112
|
2
|
4
|
4
|
100
|
2
|
4
|
4
|
First of all, I should
explain CAS. It stands for Column Access Strobe Latency, and a lower CAS number
should mean a performance increase. From other reports I have read from various
external sources, going from a 3 to a 2 yields about a 5% increase in performance
on high-end applications.
More importantly, a lower
CAS means better stability. If we look at a common combination here, 2 x 64
MB @ 133MHz, we get a latency of 2. This means that we have what is called
a 2-2-2 combination, and is something that will give you an extra performance
boost.
Keep in mind, you are
only going to get this if you have two 64 MB or 128 MB EMS chips in your computer,
and leave the other slots empty. However, if you are looking to totally upgrade
your memory, getting two 128 MB HSDRAM chips from EMS would be a solid choice.
It would definitely give you a more stabile, and more efficient system.
If you want to overclock
your system using a motherboard frequency above 133 MHz, you will no longer
be able to obtain the 2 CAS, but you will still be likely to have a solid
system up to 150 MHz. I only wish I had a motherboard available to test the
EMS memory above 150 MHz, but if I do in the future, I will be sure to update
this article and let everyone know the results.
OK, we have determined
that this is very good memory, now how much will it set you back? Currently,
one 128 MB chip runs $150, a small premium to standard SDRAM chips from other
manufacturers. So if $300 sounds reasonable for 256 MB of some of the best
memory on the market, you should probably go for it.
HSDRAM will work in any
system that can use standard SDRAM. However, you will see maximum benefit
only in systems with a high motherboard frequency. So, if you currently (or
will) have a motherboard running at 133 MHz or above, you should seriously
consider HSDRAM.
So, is HSDRAM the memory
of tomorrow? Well, some things called DDR and RDRAM are, but HSDRAM is clearly
the best memory of today, and should be a viable, stable solution for a long
time.
Eric
Murphy
00/04/18