Memory
Explained--So You Know What Your Getting
First, A Message about Bad RAM:
The gui/gcc compiler is often the first thing to die from bad RAM (or other hardware
problems that change data unpredictably) because it builds huge data structures that it
traverses repeatedly. An error in these data structures will cause it to execute an
illegal instruction or access a non-existent address. The symptom of this will be HD dying
from an unexpected signal.
The very best motherboards support parity RAM and will actually tell you if your system
has a single-bit error in RAM. Unfortunately, they don't have a way to fix the error, thus
they generally crash immediately after they tell you about the bad RAM.
The PC100 Thing:
PC100 SDRAM became a hot topic for discussion on the Internet, unfortunately what we're
finding out through a process of trial and error is that not all PC100 SDRAM is created
equal.
While most modules (more or less) work similarly at the 100MHz bus speed, pushing the
limits to 112 and the speed terror 133MHz bus speed separate the average PC100 SDRAM
modules from the Best of the Best. I've tested and compared 4 different brands and 6
different types of PC100 SDRAM. SOooo which modules shine and which aren't.
The two most important things when purchasing PC100 SDRAM are: the Quality of the Printed
Circuit Board (PCB - the board the RAM Chips are placed on) and the type and rated latency
of the SDRAMs on the DIMM and the lesser of the two when dealing with PC100 SDRAM is the
Quality of the PCB.
The reason being Intel has implemented such strict regulations and the regulations are so
strict in fact, you won't notice much difference between a PC100 Complaint module that is
manufactured on a 6-Layer PCB comparison to one manufactured on an 8-Layer PCB. The NORM
is when dealing with circuitry, in most cases the more layers you have in PCB the better
the PCB. All this crap means that basically, the PCB won't have any problems running at
bus speeds up to 133MHz, BUT the LATENCY is a different matter if you want to get pass GO.
The '-GL" and '-G8' chips are rated for a Column Access Strobe Latency Rating of 3
(RAM is accessed in Rows/Columns, the CAS rating determines how quickly a device in your
system can return a value to your RAM - lower is better), while the '-GH' chips carry a
CAS Latency Rating of 2.
Above - Samsung '-G8' Chip - CAS 3
Below - Samsung '-GH' Chip - CAS 2
At 100 & 112MHz Frequencies, the GL/G8/GH chips don't seem to show any visible
differences other than the physical markings.
However taking the '-GL/G8' chips up-ward and on-ward to 133MHz is virtually impossible,
simply because of the fact that the RAM cannot cope with such high frequencies, whereas
the '-GH' chips, which are rated for a faster CAS Latency, can cope with higher bus speeds
and will most likely work perfectly fine at the 133MHz FSB Speed.
OK, The Final Decision Time has come--what do you plan on doing with your system. You have
a high quality clockable MotherBoard like ABIT, you've purchased a 300A Celeron and need
to make a dicision on Memory.....
Well, Advanced American Megatrends checked out the BEST, closely followed by Memory Man.
The only two reasons for going with the more expensive '-GH' CAS-2 PC100 Modules are
either that you want to run upto the 133MHz bus speed, or that you have money and feel
like getting the best out there.
In conclusion, we can pretty much say that all PC100 DIMMs aren't created equal, some are
just more equal than others.
About Buying Memory:
We have both grades of memory in stock at all times and we are happy to sell you either.
Bulk memory modules are brand new memory modules---ok, made by some major brand DRAM. The
exact brand of chips vary in daily/monthly shipments. Bulk memory modules vary in specific
module configurations (lead-off timings, specific presence detect programs of the module,
chip arrangement, specific chip manufacturer, board design, trace length) and Memory
requirements for different motherboards and systems vary. The bottom line is, buy TESTED
Memory (if for no other reason--the warranty).
Most places that sell Memory don't want to invest $2000.00 in a Chip testor so they do not
have the ability to test every lot of memory.
OUR Precision brand modules are designed and manufactured to match the compatibility
requirements of each specific motherboard or specific system. We pre-program the EEprom of
each PC100 module to match the specific presence detect settings/requirements of each
specific system or motherboard. We can guarantee that only "Intel Component
Validation" passed SDRAM from factory sealed reels and high quality 100MHz, 6 layer,
high speed, low noise, module boards are used. OUR Brand are True PC100 modules and tested
AT 100MHZ before shipment to give peak perfomance in your system.
On these modules we offer a Lifetime Replacement Guarantee.
