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 p.2 #11 · Nvidia 4090 Memory Fills Up Lightroom | |
ohsnaphappy wrote:
Update
1) PC users, mostly gamers, are pretty ignorant. So if you're buying or building a PC finding rock solid info is pretty difficult. Mac users do have delusions of grandeur, haha, but at least the Mac community has some level of consensus and a reliable knowledge base.
This I would respectfully disagree with as my experience has been the exact opposite. I've been building PCs since the 90s and serious gamers are the ones trying to get every last drop of performance out of their systems, which means they are often dealing with elaborate custom systems and overclocking - this crowd is incredibly knowledgeable and the depth of that knowledge is quite something. That isn't even a thing in Mac land. The tiny performance gains they are after require very granular optimizations and a detailed understanding of how everything works. It's like anything else, there is a wide range of knowledge, some people are idiots and some are experts, and both are usually happy to "help" so the only real takeaway here is to validate your sources. If you are getting lots of ignorant responses, it probably has more to do with where you're looking (in either case).
I won't comment further on the Mac community but in either case I don't think it's fair to generalize. Both have plenty of Kool-Aid drinkers and experts alike. If you go to biased sources, expect biased information.
ohsnaphappy wrote:
5) Lastly, stop using 4 sticks of ram. Ha! OMG. I bet this drove Apple crazy when they were using Intel chips. The memory controller is dual channel and actually can't support 4 sticks. If you're using 4 sticks, you're actually using two sticks with the other two daisy chained. Yeah. Also. If you're using 4 sticks your ram is running slower, ouch, AND your CPU is running slower and can Turbo Boost less. Pretty fascinating. Even Apple has recently switched to 2x24gb configuration, correct? Very interesting.
This comment requires some important caveats - the number of memory channels your PC can take advantage is dependent on your CPU/mobo and it matters whether the memory sticks themselves are single rank or dual rank and the desired speed of said memory.
4 sticks of single rank memory will perform similar to 2 sticks of dual rank memory in most applications, but 4 sticks is harder on the memory controller. Single rank sticks are easier to run stable at higher clocks and with tighter timings, so you can run them at higher clocks and tighter timings than dual rank kits, which is why they have similar performance to the faster dual rank sticks operating at a lower frequency, all else equal.
After a certain point, if your work requires a lot of RAM, you have no choice but to go with 4+ sticks of memory due to the maximum amount of memory per stick. If your work is bottlenecked by the maximum amount of RAM you can get with 2 sticks, then no matter what you will see a performance increase doubling the capacity with 4 sticks even if they all run slower. When Apple was using Intel CPUs, DDR5 wasn't out yet, and 4 sticks vs 2 sticks was very manageable if you knew what you were doing.
On a dual channel mobo/CPU setup, the memory will run in dual channel whether you have 2 sticks or 4. On a setup that supports quad channel, it's a different story.
It also matters if you're talking DDR4 vs DDR5 because DDR5 is generally faster with 2 sticks on current memory controllers which in this generation are really struggling with 4 sticks, especially if you want to run them above base clocks (Intel XMP/ AMD EXPO enabled). For DDR4 it's a lot less of an issue and that's where 4X single rank sticks perform roughly the same as 2X dual rank sticks even in a dual channel setup. As of today, if you are using DDR5, you generally want to be using 2 sticks but only if 2 sticks can cover your capacity requirements and don't create any bottlenecks with the intended usage.
Further, it matters how your system responds to faster memory, because if the incremental gains from faster memory don't affect your usage, you can use slower sticks which will be more stable which means you can use more sticks with fewer downsides. For example Ryzen is usually more sensitive to memory speed than Intel because the infinity fabric runs at a ratio to the RAM clock up to a certain point. Also, if your CPU has an integrated GPU that you are using as your only GPU, you want to give it the fastest RAM possible as the system RAM is also serving double duty as the VRAM and GPUs are highly sensitive to VRAM speed/bandwidth.
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Interesting findings on the Lightroom / GPU front. Sounds like Adobe need to release an update!
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. This has been going on for a while and Adobe hasn't been able to fix it, at least not yet. You can try limiting your RAW cache in preferences. VRAM is also meant to be used, and the reason the 4090 is so expensive is because of all that VRAM, so if you don't limit it, expect it to be maxed out if you're doing something that can actually max it out. It is possible you are doing something that requires more VRAM, and there are GPUs with more - I don't know exactly what you're doing though.