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SDRAM SUPPORT & SDRAM Test Results
- Q. Can SIMCHECK II support PC-133
A. Yes. You will need to download the latest firmware revision and also to review
Application Note INN-8558-APN18 that discusses
- Q. What is SDRAM Technology? Can
SIMCHECK II support SDRAM modules including the PC-100 or PC-66?
A. Synchronous DRAM technology provides a revolutionary change in the way DRAM
interfaces to a computer. It synchronizes all the read/write transfers to a
system clock, thus providing significantly faster transfer rate for contiguous
(same Row Address) group of data. A Synchronous DRAM can burst up to a full
columns length of continuous data at the device clock rate (currently 100Mhz
and higher rates). Both the SIMCHECK II and SIMCHECK II se RAM testers support
our new Sync DIMMCHECK 168. This adapter readily
supports PC-100 and PC-66 SDRAM memory. You may review Application Note
INN-8558-APN14 for an explanation on how
SIMCHECK determines PC-100 compliance.
- Q. Does SIMCHECK II identify modules that
support the Athlon processor?
A. Yes, our current Sync DIMMCHECK 168 Adapter using ver. 1.49 identifies this
module by displaying "SPD=CL2 at 100MHz" in the last summary screen
as well as in the Test Log. For additional development information, please
refer to our development log.
- Q. Can I use the SIMCHECK II to program
the SPD codes of my SDRAM memory?
A. Yes. The PC Interface software allows you to edit, save, and send SPD data
to SIMCHECK II, this data can then be used to program your modules. If you do
not need to edit the SPD data, you may also elect to simply read the SPD
information from a master module into SIMCHECK II's buffer and then use this
data to program others, without using the PC Interface software. Please visit
our page on SPD Management and our page on
SIMCHECK's Production Mode for further
information. You may also consult your manual for further details.
- Q. Why can I program the SPD on some
modules and not on others?
A. The SPD chips employ a Write Protect Feature which may be active on your
module. Typical SPD chips use pin 7 for this Write Protect line. This signal
should be shorted to GND in order for the programming process to work. If this
signal has been set to Vcc or left open, the chip will not be programmable.
- Q. When using the SPD Hex Editor, why
doesn't the information change when it is sent to the tester?
A. After a change has been made in the Hex Editor, it is necessary to press
<ENTER> afterwards, so the program will receive the changed value.
Sending the SPD to SIMCHECK without pressing <ENTER> after the change
will send the former information. Further information is available from the
on-line SPD Management section and your
- Q. The SIMCHECK II memory checker shows
the speed, Tac access time, and Page Burst. Which is the most accurate
parameter for determining PC-100 compliance?
A. There are various parameters that are needed to qualify a module for PC-100
compliance. Currently all of these figures are taken into consideration before
SIMCHECK declares the module to be PC-100. You may review Application Note
INN-8558-APN14 for an explanation on how
SIMCHECK determines PC-100 compliance. Future firmware revisions may add some
additional parameters to this determination.
- Q. The SPD on the module tested says
PC-66, but the test log shows that it is PC-100 Range, will the module work as
A. All of the parameters measured indicate the module to run at a PC-100 level,
and it may very well operate as PC-100, however, please remember that modules
react differently under different loads. Some modules when used in a complete
bank will slow down to the PC-66 level. Please review Application Notes
INN-8558-APN13 and INN-8558-APN14 to review what the individual
- Q. The SPD on the memory module says
PC-100, but the test log reports it to be PC-66, is the module PC-100?
A. Due to the possibility of loading, some modules may exhibit a slow down in
speed. We recommend checking the Tac access times for further reference on
PC-100 range. Also, refer to Application Notes INN-8558-APN13 and INN-8558-APN14 to review what the individual
- Q. What Tac range is appropriate for
A. Please refer to Application Note INN-8558-APN13 for an explanation of these
- Q. During the Extensive Test, the SDRAM
module under test now runs at 83MHz. Does this mean that it is not
A. The only test that determines PC-100 compliance is the BASIC Test, so we ask
that you check the results after BASIC Test. The frequencies used in the
Extensive Test are for other tests altogether. Please refer to Application note
INN-8558-APN14 for further information on
- Q. When programming the SPD, which
locations should not be changed.
A. We recommend that the SPD information be changed by the manufacturer only.
Please refer to Application Note INN-8558-APN12 for an explanation of the SPD
- Q. Why do some SDRAM modules test faster
than others even though they are the same size, and why does the PAGE BURST
(red) LED flash on some modules and not on others?
A. Some SDRAM modules employ a FULL PAGE BURST feature. SIMCHECK II takes
advantage of this feature found in some SDRAM components and uses it to test
the modules at a faster rate (shortening the overall test time). The Page Burst
LED (red) will flash vigorously throughout the test if the module employs this
feature. Please note, however, that a full page burst is not a requirement for
PC100 or PC133 compliance. Also, those modules having such a feature will not
have an advantage in systems over those not employing this Page Burst
- Q. The red LED is still on after the Basic
Test. Is it safe to remove the module from the socket?
A. It is safe to remove memory modules when the tester is in STANDBY MODE only.
Some modules may exhibit a small current leakage that cause the red LED to
remain lit after the test has completed, this is caused by a minute voltage
that is present when the tester is in Standby Mode, however, you may safely
remove the module when no test is occurring. We do, however, strongly recommend
that the module under test remain in the socket while a test is in progress;
you should NEVER remove it while it is testing!
If you have additional questions, please feel
free to email us at firstname.lastname@example.org.
Please remember to include your phone and fax numbers.