3 ms·

I'm always a fan of bigger numbers, but I wish more time/money/whatever was put into letting DDR5 run at those XMP/EXPO speeds when using 4 DIMMs.

by AzzyHN 2y ago

imtringued 2y ago
How do you expect that to happen? By sharing memory channels you are no longer using a point to point connection and are now prone to reflections in the PCB traces where you have split the signal. There is no "money" that can be put into this, that won't also improve the performance of the single DIMM per channel setup disproportionately. I don't even understand what your point is. Quad channel support would be a much better idea since it doubles your memory bandwidth, while remaining a point to point connection, but you're going to complain that you can't add eight DIMMs then.
- zrm 2y ago
  What if you give each slot independent command pins but not a complete memory channel? What if you use a similar technology to registered or load-reduced memory, but put the register on the system board instead of the DIMM so it's in front of multiple DIMMs that then share the channel into the processor but not the traces on the system board? This may also allow higher capacity DIMMs in consumer systems.
- atlas_hugged 2y ago
  You doing ok dude?
Aurornis 2y ago
4 DIMMs on a consumer board means 2 DIMMs per channel. This is inherently a compromise in signal integrity that must come with a speed tradeoff, unfortunately. We’re dealing with laws of physics. In the past some motherboards tried a T-topology for RAM slots to optimize for 2 DIMMs per channel, but this would cause problems with 1 DIMM per channel usage. Not worth it for the average consumer.
smolder 2y ago
The way to do that would be with a chip & socket that has 4 independent memory channels (threadripper I think has eight now, but maybe used to have four?) and a many-layered motherboard that optimizes the routing and placement of each dimm slot, ideally with only 1 dimm slot per channel for maximum speed. The high end stuff with many memory channels generally isn't designed for pushing RAM clocks to gaming desktop speeds, though. You'd probably need to skip on ECC too or overclock and manually time some.

I'm always a fan of bigger numbers, but I wish more time/money/whatever was put into letting DDR5 run at those XMP/EXPO speeds when using 4 DIMMs.

by AzzyHN 2y ago

I'm always a fan of bigger numbers, but I wish more time/money/whatever was put into letting DDR5 run at those XMP/EXPO speeds when using 4 DIMMs.

imtringued 2y ago

How do you expect that to happen? By sharing memory channels you are no longer using a point to point connection and are now prone to reflections in the PCB traces where you have split the signal. There is no "money" that can be put into this, that won't also improve the performance of the single DIMM per channel setup disproportionately. I don't even understand what your point is. Quad channel support would be a much better idea since it doubles your memory bandwidth, while remaining a point to point connection, but you're going to complain that you can't add eight DIMMs then.

zrm 2y ago
What if you give each slot independent command pins but not a complete memory channel? What if you use a similar technology to registered or load-reduced memory, but put the register on the system board instead of the DIMM so it's in front of multiple DIMMs that then share the channel into the processor but not the traces on the system board? This may also allow higher capacity DIMMs in consumer systems.
atlas_hugged 2y ago
You doing ok dude?

Aurornis 2y ago

4 DIMMs on a consumer board means 2 DIMMs per channel. This is inherently a compromise in signal integrity that must come with a speed tradeoff, unfortunately. We’re dealing with laws of physics. In the past some motherboards tried a T-topology for RAM slots to optimize for 2 DIMMs per channel, but this would cause problems with 1 DIMM per channel usage. Not worth it for the average consumer.

smolder 2y ago

The way to do that would be with a chip & socket that has 4 independent memory channels (threadripper I think has eight now, but maybe used to have four?) and a many-layered motherboard that optimizes the routing and placement of each dimm slot, ideally with only 1 dimm slot per channel for maximum speed. The high end stuff with many memory channels generally isn't designed for pushing RAM clocks to gaming desktop speeds, though. You'd probably need to skip on ECC too or overclock and manually time some.