Masroor said:
Dear All,
I have a Dell Optiplex GX620 computer bought about two years back. The
specs are: Intel Pentium 4 EM64T 3.0 GHz processor, 800 MHz FSB, Intel
945G Chipset. There are four DIMM slots. In three slots I have put
already put three RAMs, two 256 MB each, one 512 MB. All are 533 MHz
DDR2.
Computer specification says that the RAM is upgradable up to 4GB. With
only one free slot available, and RAM price going down, I want to use
it to its maximum capability. Now, I can not find out how much maximum
RAM I can put in the free slot? Is it 4GB - (256MB X 2 + 512 MB) =
3GB? Or is it 4GB/4 = 1GB.
Hope I have been able to explain the situation.
Stores over here have a nonrefundable policy. So, I can not simply buy
and experiment.
Can you please tell me maximum how much RAM in the free slot?
Thanks in advance.
http://www.crucial.com/store/listpa... (Desktop, Mini-Tower, and Small Form Factor)
"Each memory slot can hold DDR2 PC2-5300,DDR2 PC2-4200,DDR2 PC2-6400
with a maximum of 2GB per slot."
The largest stick would be a 2GB stick.
For best performance, memory should be installed in matched pairs. Or
at least the amount of memory in each channel should be equal. The
motherboard has two channels. (I have included some example configurations
further down in this post.)
http://support.dell.com/support/edocs/systems/opgx620/en/ug/A02/memory00.htm#wp1105370
(Picture)
http://support.dell.com/support/edocs/systems/opgx620/en/ug/A02/memora14.jpg
matched pair of memory modules in connectors DIMM1 and DIMM2 (white securing clips)
matched pair of memory modules in connectors DIMM3 and DIMM4 (black securing clips)
The 945G Northbridge on the motherboard is actually more flexible than those instructions
imply.
"Addressing Memory With 4-GB Configurations
This computer supports a maximum of 4 GB of memory when you use four 1-GB DIMMs
or two 2-GB DIMMs. Current operating systems, such as Microsoft Windows XP, can
only use a maximum of 4 GB of address space; however, the amount of memory
available to the operating system is less than 4 GB. Certain components within
the computer require address space in the 4-GB range. Any address space reserved
for these components cannot be used by computer memory."
What that last paragraph means, is if you installed a total of 4GB of memory, about
3.2GB or so would be visible in Windows. Due to address space limitations, the other
0.8GB would not be accessible by the processor (could not be reached).
Considering the low price of memory, a good purchase would be to buy two
matched 1GB sticks. Remove the current memory from the computer, and install
2x1GB in DIMM1 and DIMM2. That leaves room for a future purchase of another
2x1GB of memory. When you purchase the first 2GB total of memory, you will get to
use all of it, as there is no address conflict at the 2GB level.
A 2GB kit should be pretty cheap. $38 USD for this kit of two sticks of memory.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820141017
For dual channel operation, the 945G Northbridge is flexible on memory.
To get dual channel operation, the amount of memory in each channel should
be equal. DIMM1 + DIMM3 = DIMM2 + DIMM4. So for dual channel, you could:
256MB + 256MB = 512MB + (zero)
By adding just one stick of size 512MB, and moving the sticks around, you
could use this configuration. (Total of 1.5GB of memory)
256MB + 512MB = 256MB + 512MB
Buying 2x1GB configuration, looks like this with the other memory removed.
1GB + (zero) = 1GB + (zero)
And later, when you add two more 1GB sticks, it becomes
1GB + 1GB = 1GB + 1GB
All of those configurations would be dual channel capable, for best performance
(better memory bandwidth). Unbalanced configurations lead to single channel
operation, and a reduction in memory bandwidth. If installed correctly,
even your current collection of memory could be operating in dual channel
mode.
Paul
