Benny said:
Bought a new PC in January.
Specs are:
Windows XP Pro SP3
Gigabyte mobo (GA-EP45T-UD3R) with 4 slots (2 channels) for DDR3 RAM.
I bought the PC with 2 x 1Gb Corsair DDR3 1333 MHz RAM.
I have now bought 2 more of exactly the same Corsair RAM.
After installing the extra RAM, Windows will not open fully. The PC only
gets as far as the Windows XP screen and then goes blank.
I even went into the BIOS but that froze after a short time as well.
I have removed the extra RAM and all is good again.
How can I get the extra RAM to work?
regards
PeterH
I agree with the other posters, that you should test the two new memory
DIMMs separately, from the memory that you know is working well.
For advice on "voltage", you can download a specification sheet for
your Corsair product. Go to corsairmicro.com and try and locate
the product. The package the memory came in, probably has
the exact part number. This is just a guess on my part, as to
what you bought (this is a 2x1GB DDR3-1333 kit). Corsair have many
different kits, so I could easily select the wrong one.
http://www.corsair.com/_datasheets/TWIN3X2048-1333C9.pdf
Nominal memory voltage for DDR3 is 1.5V. That is the value
that JEDEC agreed to, for the DDR3 generation of RAM. To attain
the higher speeds of enthusiast RAM, the voltage is *increased*.
The value shown in that sheet is 1.7V . On page 40 of the motherboard
manual, I see an entry "DRAM Voltage" [1.5} and "DRAM Termination" [0.75].
To start out, you'd expect the termination voltage to be midway, between
supply and ground. I'd adjust that to
"DRAM Voltage" [1.70V]
"DRAM Termination" [0.85V]
It is possible, whoever set up your system the first time, has
already made that adjustment. They may have downloaded the
datasheet for the first two sticks, when the first two sticks
were purchased. And got the "DRAM Voltage" number from there.
When extra memory is added, you would *not* reduce that setting.
You see the recommended value in the spec sheet, and that is
the voltage that Corsair chose, for their memory testing at
the factory. If you drop the voltage, you'd have to slack
off on the timing settings in order to keep the memory stable.
Or even operate it at a lower speed.
Since the memory in that example, uses a "JEDEC standard" SPD, that
means none of the several extensions to JEDEC, are being used to
control the automatic setup of the memory. JEDEC doesn't have
a way of setting the voltage automatically. When using enthusiast
memory, it is the responsibility of the user/builder, to set
the voltage appropriately.
If you've actually *mixed* two sets of products in the same
computer, they should have something close to the same
voltage requirements. For example, installing a 1.5V product and
a 2.1V product, and then expecting to find a "sweet spot" for the
result, is asking for trouble. Sometimes, a low voltage is stated,
because the memory is known to "burn up" at high voltage. My
previous computer used low voltage memory, and I would never
consider cranking it to really high values. To get an understanding,
for the unstated characteristics of the memory, you have to
check forums or enthusiast sites, or the Newegg reviews, to
get some idea what the stuff is.
So, I think you have the wrong idea about voltage. This is a summary.
1) JEDEC set the voltage to 1.5V . JEDEC also designated standard speeds.
2) The memory industry always tries to surpass what JEDEC says. They
try to run the memory at higher speeds. And that means increasing
the voltage, to make it stable.
3) The voltage spec in the data sheet can mean two things. It can
mean "hey, it was stable at 1.7V, and it'll take a lot more" or
it could mean "ooh, if you use more than 1.7V, it'll burn up".
A dash of common sense, and/or luck, is needed to interpret
exactly what they mean. (They're hardly likely to admit the
stuff burns up at high voltage. Some memory companies would
rather be smothered in warranty claims, than admit to anything.)
The first reviewer comment here:
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16820145183
Panzerfinder15 Great for price, fast, no complaints 6/6/2009 12:59:43 PM
Cons: none whatsoever, other than they updated their sticks between January
and now (run different voltages) I'm running all four at the higher of
the 2 V ratings, and they are stable. (they run lower voltage now
1.6v vs. 1.75v, i think)
So it is possible for a product to change specs, between buying two
different pairs. Normally, you'd hope the spec sheet would track
this, but again, marketing being what it is, they may change the
product, and only "tech support" knows the secret. Tech support
may say "is that Version 2 or Version 3" of the module. And
that may be the first inkling you get, they've been screwing
around.
Corsair have forums, so you can check in there and ask questions.
Be prepared to verify the exact part number on both pairs, since
it is possible there is a subtle difference between them. If they
change chip types (which you cannot see because of the stupid
heat spreaders), then it is possible taming them will be more
complicated. They may even suggest returning them, and replacing
them with something else.
http://forum.corsair.com/v3/index.php
If they were mine, I'd test the two sticks separately, to see first
of all, whether they can be tamed by themselves. Set them to the
spec values shown on the product package. Test with memtest86+
and then boot into Windows and run Prime95. If the sticks don't
work, send them back, and eat a restocking fee. Or whatever.
Another way to handle the problem, would be to buy 2x2GB matched,
and put the old ones safely in a drawer somewhere for a rainy day.
I don't know all the tricks for DDR3, and there are sites which
have tweaked those things to death. Try here for example.
http://www.xtremesystems.org/forums/forumdisplay.php?s=&f=233
Another parameter to consider, would be "Command Rate". When using
four sticks, or running sticks at extremely high speeds, that should
be set to "2T". That increases setup time to rising clock edge.
And I don't understand why the Gigabyte manual says the setting
varies from 1-3. The choices should be 1 or 2. 1 is tight,
2 is slack and helps at higher speeds.
Good luck,
Paul
