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It's a mystery to me why graphics cards have hardwired RAM. For CPUs/motherboards RAM has been extensible for decades.
by cubefox 3y ago
It's a mystery to me why graphics cards have hardwired RAM. For CPUs/motherboards RAM has been extensible for decades.
- alargemoose 3y agoYhe main reason is speed. For example DDR5 has a transfer rate of about 50GB/s. The GDDR6X used in GPUs has a transfer rate of about 1TB/s. Nvidia just announced H200 AI processors have HBM3e memory that they report can go as fast at 10TB/s.
- ElectricalUnion 3y agoSpeed/signaling issues. To me is a mystery that CPUs/motherboards still have extensible RAM, integrated RAM (if you don't skimp and go for cheap RAM) can be very fast - for example the Steam Deck has quad-channel 5500 MT/s LPDDR5, very console-like.
- muttled 3y agoWhat is it that make extensible RAM inherently slower? Is it the connectors raised off the boards, adding physical distance to the traces that's the issue?
- ElectricalUnion 3y agoThe mechanical connector layout forces sub-optimal signalling paths. You're forced to make everything slower to make things consistent. That being said, a more optimized connector, board layout and form factor could make large-capacity, lower-latency modules possible. Not sure for example if there is anything out there besides the Dell proposed CAMM form factor, and I don't remember that one being specifically promoted as "faster", mostly "smaller".