3 ms·

I'm a bit confused, DDR5 products are already out - as are CPUs and motherboards that support them. How can this change happen retroactively? Would motherboard

I'm a bit confused, DDR5 products are already out - as are CPUs and motherboards that support them. How can this change happen retroactively? Would motherboard manufacturers just need to update the BIOS to enable new XMP configurations? (For when this new, higher transfer rate RAM becomes available)

braiamp 3y ago
> while leaving the spec open to further expansions with faster memory as technology progressed They only set the current standard, but allowed to, if technology progresses, that other speeds/timings would also be jedec compatible, rather than being some kind of XMP. Motherboard manufacturers do not need to upgrade their previous models if the hardware doesn't meet the required SN ratios, or whatever. But they _could_ if they believe they had the hardware to support it.
tadfisher 3y ago
Not even that; this just sets standard speed/latency values for memory modules without XMP. You can already exceed these numbers with XMP. PRAC would need handling in the memory controller, so that would require a CPU update if I understand correctly.
- doikor 3y ago
  PRAC should happen automatically in the background when possible and when it really needs to stop the controller from accessing something while waiting for the bits to refresh it uses the already existing ALERTn signal. https://stefan.t8k2.com/rh/PRAC/index.html https://stefan.t8k2.com/rh/PRAC/index.html > Panopticon retrofits an existing signal in the DDR specification, called ALERTn, to effectively “trick” the memory controller to pause issuing new DDR commands. DRAM uses ALERTn to signal errors to the memory controller. Upon receiving this signal, the memory controller stops issuing new DRAM commands and instead re-issues the old memory access. By making use of ALERTn, Panopticon requires no modifications to any hardware other than DRAM itself. (As I understand PRAC uses the same design as Panopticon for this part)
dist-epoch 3y ago
The spec is just a bunch of numbers which are already configurable and motherboards can already be set at much higher frequencies. It doesn't mean that any particular combination of CPU/motherboard/RAM will work.
imtringued 3y ago
It doesn't. If you buy A DDR5-6400 DIMM it doesn't get updated to 8800. It will stay at 6400. This just means that manufacturers will be able to brand their tested DDR5 DIMMs as supporting 8800. You still need a CPU and Mainboard that has been validated at those speeds. You're going to need a 8700G if you actually want to hit those speeds by the way.

braiamp 3y ago

> while leaving the spec open to further expansions with faster memory as technology progressed They only set the current standard, but allowed to, if technology progresses, that other speeds/timings would also be jedec compatible, rather than being some kind of XMP. Motherboard manufacturers do not need to upgrade their previous models if the hardware doesn't meet the required SN ratios, or whatever. But they _could_ if they believe they had the hardware to support it.

tadfisher 3y ago

Not even that; this just sets standard speed/latency values for memory modules without XMP. You can already exceed these numbers with XMP. PRAC would need handling in the memory controller, so that would require a CPU update if I understand correctly.

doikor 3y ago
PRAC should happen automatically in the background when possible and when it really needs to stop the controller from accessing something while waiting for the bits to refresh it uses the already existing ALERTn signal. https://stefan.t8k2.com/rh/PRAC/index.html https://stefan.t8k2.com/rh/PRAC/index.html > Panopticon retrofits an existing signal in the DDR specification, called ALERTn, to effectively “trick” the memory controller to pause issuing new DDR commands. DRAM uses ALERTn to signal errors to the memory controller. Upon receiving this signal, the memory controller stops issuing new DRAM commands and instead re-issues the old memory access. By making use of ALERTn, Panopticon requires no modifications to any hardware other than DRAM itself. (As I understand PRAC uses the same design as Panopticon for this part)

dist-epoch 3y ago

The spec is just a bunch of numbers which are already configurable and motherboards can already be set at much higher frequencies. It doesn't mean that any particular combination of CPU/motherboard/RAM will work.

imtringued 3y ago

It doesn't. If you buy A DDR5-6400 DIMM it doesn't get updated to 8800. It will stay at 6400. This just means that manufacturers will be able to brand their tested DDR5 DIMMs as supporting 8800. You still need a CPU and Mainboard that has been validated at those speeds. You're going to need a 8700G if you actually want to hit those speeds by the way.