16MB 72pin SIMMs, 2x8 vs 4x4 performance on 486DX4-100 \ VOGONS

16MB 72pin SIMMs, 2x8 vs 4x4 performance on 486DX4-100

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First post, by torindkflt

Posted on 2015-06-04, 23:54

torindkflt Offline

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Looking for some more information regarding my current 486 rebuild. Motherboard is a QDI V4P895GRN/SMT with an Am486DX4-100V8T processor. It will eventually be running the RTM version of Windows 95. I want it to have 16MB of RAM, which is what the original system I am attempting to recreate had.

Now, here's my question...assuming that all of the memory being used is 70ns FPM, would there be any performance penalty or benefit from using four 4MB SIMMs instead of two 8MB SIMMs, or vice-versa? I ask because the original system had 2x8, but the motherboard I received from eBay for my rebuild included 4x4. I want this rebuild to be as accurate to the original as possible, and any performance differences that come from using 4x4 instead of 2x8 would be unacceptable to my nostalgia's OCD. 🤣

Reply 1 of 3, by smeezekitty

Posted on 2015-06-05, 00:14

smeezekitty Offline

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The RAM speed doesn't change by itself. I can't say if you could run tighter timings one way or another. It depends on several factors.
If you have an OEM BIOS that doesn't let you set the RAM Speed, it won't make a difference anyway.

Reply 2 of 3, by torindkflt

Posted on 2015-06-05, 00:30

torindkflt Offline

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I'm not looking to improve the performance by changing settings in the BIOS. Rather, I'm looking to see if there's be a default-settings difference in performance between those two configurations. Many many years ago, I heard that there is a slight difference in access speed/latency when it comes to accessing many smaller memory modules compared to fewer larger modules, but whether this is true or not I do not know.

Reply 3 of 3, by Anonymous Coward

Posted on 2015-06-05, 00:31

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I don't believe the OPTi 895 chipset on your motherboard supports bank interleave, so there should be no difference between 4x4, 2x8 or 1x16.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

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