DDR5 latency way too high?

[whm1974]

I did read/watched some articles on DD5 when those Modules came out. One thing I can see that needs to be fixed that results in poor performance is the high latency. 36ns is rather on the high side for System RAM. Even for new types of Memory. Not that I'm building a new Rig or anything. I do however expect reasonable performance.

 

I will need to read some articles again, but I do recall the RAM being DDR5-6400 or such. Due to high price tag and hard to get, doubtful anyone will be buying anytime soon.

[RONOTHAN##]

2 minutes ago, whm1974 said:

36ns is rather on the high side for System RAM.

You've never used a Ryzen CPU 5000 series then, 55ns measured latency is considered about as good as you can get with daily stable settings. 

 

Also where'd you get 36ns from? Theoretical first word latency for the slow 4800MT/s CL40 kits is 16.7ns, and actual to core latency is closer to 60ns+ on the slow kits and 50ns is on the good 6000+ kits with tight timings. Part of the reason the latency is so slow for DDR5 is because the memory controller is running at half speed (Gear 2), so data is only being transferred to the cores from the memory controller half the amount it would on DDR4 in Gear 1. 

[Guest]

It's new. DDR4 was just as expensive when released. Kits up at 600$ I have a set that was 350$. Now to be had for far less. Because DDR4 is played out. 

No more bandwidth to meet the demands of future CPU architectures. Watch how it works, past to present. 

CPU with more cache favors high bandwidth System memory. 

 

"Latency woes" -

 

It's in nanoseconds. If you can measure this amount of time with a single thought, you'd be the smartest joe I know.

 

50 ns (Nano seconds) , well that's 1 nano second = ONE BILLIONTH OF A SECOND. 

 

so griping over 50 to 75 nanoseconds is a far cry from anyone to actually need to worry about it. 

 

"Oh no, my latency is 50 billionths of a second...."

 

lol. see what I mean? You guys should look for high frequency over latency. Latency goes hand in hand with CPU architecture overclocking also. CL 40 at 6400mt/s is 3200MHZ which DDR4 is half of. 

 

It was curious to see 12th gen support both ddr4 and 5, but hey, a company needs to make sales right? So that's what they did. It was a good strategy in the current market.  

 

 

[whm1974]

16 minutes ago, RONOTHAN## said:

You've never used a Ryzen CPU 5000 series then, 55ns measured latency is considered about as good as you can get with daily stable settings. 

 

Also where'd you get 36ns from? Theoretical first word latency for the slow 4800MT/s CL40 kits is 16.7ns, and actual to core latency is closer to 60ns+ on the slow kits and 50ns is on the good 6000+ kits with tight timings. Part of the reason the latency is so slow for DDR5 is because the memory controller is running at half speed (Gear 2), so data is only being transferred to the cores from the memory controller half the amount it would on DDR4 in Gear 1. 

The 36ns is what I can recall DDR5-6400 being from the Articles/Videos themselves. Do remember the poor performance compared with DD4-3200.

 

Best to wait until DDR5 improves, pricing, and becomes more widespread.

[Guest]

1 minute ago, whm1974 said:

Best to wait until DDR5 improves, pricing, and becomes more widespread.

Next 2 platforms, by the end of the year.... DDR4 is EOL.

[whm1974]

1 minute ago, Guest 5150 said:

Next 2 platforms, by the end of the year.... DDR4 is EOL.

Don't ring the Bell Tower on DDR5 just yet. It took some time for DD4 to replace DDR3. Same thing thing for DDR2 to do the same for DDR.

[Somerandomtechyboi]

1 minute ago, Guest 5150 said:

Next 2 platforms, by the end of the year.... DDR4 is EOL.

13th gen will most likely support ddr4 so one last gemeration and after that its ddr5, though pretty sure when 14th gen comes along ddr5 will be more worth it cause better imc

 

7 minutes ago, Guest 5150 said:

You guys should look for high frequency over latency. Latency goes hand in hand with CPU architecture overclocking also. CL 40 at 6400mt/s is 3200MHZ which DDR4 is half of. 

^^^

ddr5 has mostly the same latency as ddr4 but much more bandwidth than ddr4 which is pretty much the reason why we keep making new gens of ram, i mean my ddr2 at 1470 7-9-6-9 does 10400 read w latency ~60ns while newer ddr4 has over double the bandwidth even if it is the same latency

 

If selling oced bare pcbs ever takes off both ddr3 and ddr4 maybe ill jump into  ddr5 abit early at 14th gen

[Guest]

Just now, whm1974 said:

Don't ring the Bell Tower on DDR5 just yet. It took some time for DD4 to replace DDR3. Same thing thing for DDR2 to do the same for DDR.

It will take some time. I'm into DDR4 yet myself because have better things to spend money on, like window tint and wheel spacers for my 02 MK4. Just installed a new Double Din 10" Android 11 quad core stereo also. Has a nice little 10" sub in the trunk and a little weight reduction as well.  

[Guest]

14 minutes ago, Somerandomtechyboi said:

13th gen will most likely support ddr4 so one last gemeration and after that its ddr5, though pretty sure when 14th gen comes along ddr5 will be more worth it cause better imc

 

^^^

ddr5 has mostly the same latency as ddr4 but much more bandwidth than ddr4 which is pretty much the reason why we keep making new gens of ram, i mean my ddr2 at 1470 7-9-6-9 does 10400 read w latency ~60ns while newer ddr4 has over double the bandwidth even if it is the same latency

 

If selling oced bare pcbs ever takes off both ddr3 and ddr4 maybe ill jump into  ddr5 abit early at 14th gen

I certainly can't read the future, but the past tells quite a bit. I have a lot of old hardware. The point where generations lapsed. Even had an Old AsRock board that was s939 and with a Riser card could install AM2 processors and ddr2 memory. It really was a creature of sorts. I blew my FX-55 and the board up with a volt mod. lol. It was AsRock Dual Sata II 939. What a killer board and time to have been into PCs and overclocking. A lot of interesting stuff has happened during transitions. People really should try and embrace all they can. Understand it, not just know it. 

 

Here's the transition. s939 to AM2 4000+ Double the L2 cache, leaving DDR1 for DDR2 and secure the bandwidth for dual cores.

They decided, double the cores, double the bandwidth. Frequency from 200mhz to 400mhz. Latency, shit about the same as it's always been. Within a certain threshold they design the Cache to operate. Be it frequency or architecture change or both.

 

Architecture stays the same below - Doubled the cache, double the core count, doubled the memory bandwidth.

s939

https://www.cpu-world.com/CPUs/K8/AMD-Athlon 64 4000+ - ADA4000DKA5CF (ADA4000CFBOX).html

sAM2

https://www.cpu-world.com/CPUs/K8/AMD-Athlon 64 X2 4000%2B - ADO4000IAA5DD (ADO4000DDBOX).html

 

So why not go back to X58 triple channel? It's not cost effective to justify the performance gains. So it didn't take off. 

 

When a pro gamer spends 5,000 to over 10,000 US dolla, This small elite company might buy into ThreadRipper. Cause well, money is plentiful and the hardware is available. 

 

But you don't see a lot of talk about thread ripper processors much. Niche market. DDR5 will be mainstream. Probably for 4 or 5 years if I where to guess. Just depends when the CPU needs cap out the available bandwidth. 

 

Oh, and same goes for your video cards and hard drives. PCI-E lanes, nobody talks about the latency here.... they just want PCI-E 4.0+++ cause FASTERER. 90% just simply don't know why....

 

Really all this is the same as it's been in the past. Hasn't changed much. The frequency clubs keep changing though. 4ghz club. 6ghz club, 8ghz club. DDR4 3000mhz ddr4 6000 club. Now you want to join the DDR5 8000mt/s 4000Mhz club.... 

 

But yeah. pretty much that stuff. sorry for the ramble.

[RONOTHAN##]

30 minutes ago, whm1974 said:

The 36ns is what I can recall DDR5-6400 being from the Articles/Videos themselves. Do remember the poor performance compared with DD4-3200.

 

Best to wait until DDR5 improves, pricing, and becomes more widespread.

I really am confused where they got that number from though, It's no where close to where calculated latency would be, and in the programs I know of to check mem to core latency (Intel MLC and Aida64 Memory Latency Test) 36ns is where very good, latency optimized, daily stable overclocks land. It would be very useful to link those specific articles that you're referring to though, since AFAIK DDR4 3200MHz CL16 and DDR5 6400MHz CL32 should be effectively the same latency but DDR5 should be over double the bandwidth. 

 

I agree it's still best to avoid DDR5, mostly because the Alder Lake memory controller is about as janky as they come with DDR5 support, but pricing is starting to come down and it is starting to make more and more sense to get. Once AM5 comes out, has a more mature memory controller that won't completely suck, and has boards with more competent memory topologies, I'd expect DDR5 adoption to increase swiftly and it to actually start making sense with some of the higher speed kits. It's definitely new technology, but it'll get there at some point.

 

Part of the problem is that DDR4 was just so good. Samsung B die was basically the perfect memory chip for performance, it timed about as tight as you could go on the registers on all the secondary and tertiary timings, it clocked very well (not as good as some other kits but still did do 5GHz on the good kits), plus all the primary timings went incredibly low as well. DDR5 will eventually beat that, it's a question of when, not if, but it has some very stiff competition for latency because of just how good DDR4 latency got. 

[Somerandomtechyboi]

32 minutes ago, Guest 5150 said:

DDR5 will be mainstream. Probably for 4 or 5 years if I where to guess. Just depends when the CPU needs cap out the available bandwidth. 

Well ddr4 lasted for 8 years with ddr3 lasting ~7 years so either ddr5 lasts longer or itll break this trend and last a shorter time

 

3 minutes ago, RONOTHAN## said:

Part of the problem is that DDR4 was just so good. Samsung B die was basically the perfect memory chip for performance, it timed about as tight as you could go on the registers on all the secondary and tertiary timings, it clocked very well (not as good as some other kits but still did do 5GHz on the good kits), plus all the primary timings went incredibly low as well. DDR5 will eventually beat that, it's a question of when, not if, but it has some very stiff competition for latency because of just how good DDR4 latency got. 

Then theres also the perfect dirt cheap budget chip which is 8gbit rev e, 20$ for 2666 bare pcb crucials with anything from d9vpp to c9bjz in terms of ic bin and capability of 4600+ c18 assuming board and cpu arent an issue, also being very light on the imc which means possibility of dual rank at high speeds

 

Add to that stupid high bin hynix djrs that can do 5600+ on air if pushed to 1.7-1.9v like on those 5333 bin kits with loose timings, sure latency isnt great but bandwidth go brrrrrr

 

Though ddr4 is best ran with dual rank and i doubt 5000+ is possible without subzero cpu, rev e will prob come the closest since its very light on the imc. ddr5 on the other hand doesnt benifit much from dual rank which means single sided configs go vroom vroom once ddr5 matures and ~7200 becomes standard