HN article above this one: "Going faster doesn’t make you happier.." :)
DDR5 memory is on its way, twice as fast as DDR4
11–20 of 74 posts
Re: DDR5 memory is on its way, twice as fast as DDR4
#12Would the equivalent amount of DDR5 actually feel any different to DDR4 to the end user? It seems like hardware is getting better but basic software (web browser etc) is getting more complicated/bloated at the same rate, so things don't actually feel 10x faster than they did a few years ago.
Really? Go back and install Windows 7, then Windows XP, then Windows 98. Tell me the boot times and how long until a browser opens. :D I think our expectations are just getting higher.
He may have been referring to Wirth's law.
From wikipedia
Wirth's law is a computing adage which states that software is getting slower more rapidly than hardware becomes faster.
Re: DDR5 memory is on its way, twice as fast as DDR4
#13"Analysts didn't expect DDR5 to be developed"
Is that the same analysts stating that Apple will have an event at the same time as last year?
If an improvement can be done cheap and easy it will be done. Implementing a memory controller for DDR5 is probably a trivial job very similar to current DDR4.
Integrated GPUs has been on the rise for a long time. This is good news for reusing current memory controller designs while providing higher bandwidth.
Re: DDR5 memory is on its way, twice as fast as DDR4
#14JEDEC officially specs DDR4 RAM up to 2133 MHz. But manufacturers seem to have left this far behind already, with Corsair and G.Skill shipping modules at 4200 MHz. I don't see why JEDEC doesn't just add a few more rows to the table of official speeds. The only real advantage for a new spec is to bump the density.
Re: DDR5 memory is on its way, twice as fast as DDR4
#15So, it's been a while since I tinkered with hardware, but I'm making the blind assumption that although the bus speed is twice as fast as DDR4, there is also twice the read latency, as has always been the case with DDR memory, meaning the net read latency improvement is basically nil. Of course we expect every generation of Double Data Rate memory to double the data rate. But it's always been a bit misleading to say…
Yes, I always considered that inflated bus speeds a scam. It is like having a subway line driving trains every 2 minutes, but only 1 train in 15 taking passengers, rest going completely empty. If you look at CAS latencies [1] then it's clear that memory speeds stagnated a long time ago: [1] https://en.wikipedia.org/wiki/CAS_latency
That's not a very accurate analogy, since sequential reads do improve. CAS latency is one limiting factor on random reads, which has been constant / only slightly improving for a very long time; significant improvements last happened here around with DDR and SDR (i.e. 20 years ago).
This is a central reason why the cache size per thread has not changed much in the last 20 years (beside of course fabbing/yield limits). (And because caches are subject to a similar effect as Dennard scaling)
(btw. I wonder if it'd have been smarter by the memory industry if they specified latencies in absolute numbers (or relative to the memory array clock, not the bus clock), not bus cycles, since the rising latency numbers have been a marketing issue in every generation.)
Re: DDR5 memory is on its way, twice as fast as DDR4
#16Would the equivalent amount of DDR5 actually feel any different to DDR4 to the end user? It seems like hardware is getting better but basic software (web browser etc) is getting more complicated/bloated at the same rate, so things don't actually feel 10x faster than they did a few years ago.
Do you have an SSD yet? A good one?
Computers with good SSDs and not too much bloatware (relevant on Windows) do feel faster to me than computers used to be.
I think people can get nostalgic accidentally and overestimate how fast things were in the past. I remember multi-minute loads for games on my Commodore 64. I remember multi-minute Windows 3.1 bootups. I remember watching a JPEG progressively creep in on the early web. I remember watching my school projects in C++ take noticeable time to compile despite what we would now consider their absurdly simple nature. I remember when I was reluctant to click on a 1MB download.
But you do want to avoid having a modern Windows machine on a slow spinning-rust hard drive. Yeow.
Re: DDR5 memory is on its way, twice as fast as DDR4
#17Earlier quoted context omitted.
Yes, I always considered that inflated bus speeds a scam. It is like having a subway line driving trains every 2 minutes, but only 1 train in 15 taking passengers, rest going completely empty. If you look at CAS latencies [1] then it's clear that memory speeds stagnated a long time ago: [1] https://en.wikipedia.org/wiki/CAS_latency
That's not a very accurate analogy, since sequential reads do improve. CAS latency is one limiting factor on random reads, which has been constant / only slightly improving for a very long time; significant improvements last happened here around with DDR and SDR (i.e. 20 years ago). This is a central reason why the cache size per thread has not changed much in the last 20 years (beside of course fabbing/yield limits)…
If cas latency haven't changed for 20 years, and the memory wall in general being a huge pain, does anybody know why didn't some sort of 2.5D memory(even using low-resolution lithography and carriers cheaper than silicon), haven't entered the market ?
Re: DDR5 memory is on its way, twice as fast as DDR4
#18JEDEC officially specs DDR4 RAM up to 2133 MHz. But manufacturers seem to have left this far behind already, with Corsair and G.Skill shipping modules at 4200 MHz. I don't see why JEDEC doesn't just add a few more rows to the table of official speeds. The only real advantage for a new spec is to bump the density.
>> The only real advantage for a new spec is to bump the density.
And DDR4 can apparently support 128GB per module. Those apparently exist, but you can't find even a 32GB at Newegg.
Re: DDR5 memory is on its way, twice as fast as DDR4
#19Are there applications which will see significant benefit from a new generation of DRAM, or higher speeds?
Games, for instance, seem to see only very small performance differences from changing RAM speeds.
Re: DDR5 memory is on its way, twice as fast as DDR4
#20Are there applications which will see significant benefit from a new generation of DRAM, or higher speeds? Games, for instance, seem to see only very small performance differences from changing RAM speeds.
Games are a special breed of application since they delegate a lot of work to the GPU and often are GPU-bound, not CPU-bound. Other workloads often end up with the CPU waiting for memory accesses. The most obvious example, besides stream-processing, would be garbage-collected languages. Simply scanning the heap will benefit from all the memory bandwidth it can get.
Even if speeds don't improve perceptibly because the CPU is simply waiting for the human 99% of the time it still may benefit laptop battery time due to increased power efficiency and the CPU completing that 1% sooner and returning to low power states.