Nvidia RTX 30xx

[RobertJasiek]

lightvector, what to choose for an SSD: high sequential speeds, high 4K random access speeds or a reasonable combination of both?

[gennan]

I think the disk is not used much after loading the network in memory (when starting up KataGo). So it shouldn't matter much?

[RobertJasiek]

A few months ago, igorslab tested RTX quadro 6000, RTX 2080 TI and slower cards for 3D games. PCIe 3.0 x8 is a bit too slow with 0% - 6% speed loss (especially for lower display resolution when the CPU has to do more because the GPU does less) while PCIe 3.0 x16, PCIe 4.0 x8 and PCIe 4.0 x16 are fast enough.

For dual card use and PCIe 4.0 x8, things are unclear for RTX 3080 and 3090: we need to await tests as soon as the NDA will be lifted in a few days.

I think that deep learning is closer to high than low resolution: the GPU has to do more than the CPU so speed losses should be nearer to the lower end. Nevertheless, with the circa. 1.5x acceleration of the new Nvidia cards, PCIe 4.0 x8 versus PCIe 4.0 x16 might play a role.

If the difference turns out to be up to ca. 3%, we can neglect the problem and, for dual use, some motherboard with two PCIe 4.0 x8 slots in dual use would be good enough. If, however, the difference is larger than 6%, we prefer some motherboard with two PCIe 4.0 x16 slots in dual use, provided prices of them and their fitting CPUs are not astronomic.

SSDs hit PCIe 4.0 x16 limits faster than GPUs. Currently, I see no danger of 100% speed loss for fastest GPUs despite PCIe 4.0 x16 being up to 100% faster than PCIe 4.0 x8. Small percentages appear to be the order of magnitude of speed losses.

[RobertJasiek]

As I am learning hardware aspects, I can share some:

Since RTX 3080 / 3090 are heavy, it is wise to support them by a pillar.

A 300W graphics card needs +100W extra safety for the power supply. These cards have 320 / 350W so each needs more than +100W. This is besides the basic extra safety for the mainboard.

If you want to use or consider the option of later using 2 such graphics cards, you must choose the mainboard carefully, reading specifications and handbooks. Having two PCIe x16 slots is insufficient. Mainboard manufacturers like to advertise with x16 and hide the fine print, which is the PCIe version combined with the numbers of lanes available for the slots when used together. The following operation modes work for two "PCIe x16" slots occupied by two fast graphics cards in "dual" mode, presuming a CPU with suitable PCIe functionality:

PCIe 4.0 x16 + PCIe 4.0 x16 (best; currently unavailable; maybe by Zen3)

PCIe 4.0 x8 + PCIe 4.0 x8

PCIe 4.0 x8 + PCIe 3.0 x16 (same speed as before)

PCIe 3.0 x16 + PCIe 3.0 x16 (currently the best of Intel)

Beware of the following trap, which occurs for many mainboards (such as with B550 chipset or moderately priced X570): PCIe 4.0 x16 + PCIe 4.0 x4. Your second graphics card would be too slow!

Typical extra expenses for 2 instead of 1 fast graphics cards are +70€ power supply, +150€ mainboard, +130€ CPU, +50€ larger case, maybe +50€ coolers. (Watercooled graphics cards would shoot the total amount to the space and create technical risks.)

[RobertJasiek]

First 3D gaming benchmarks comparing RTX 3090, 3080 and 2080TI say that the relative differences between these cards are similar and 3090 compared to 3080 is ca. 19% faster on average with values 15~21%.

Under non-overclocking load, a 3080 FE consumes 320 ~ 450W. OEM 3080 consume 340 ~ 470W. Add the other PC components (among them ca. +35% for the CPU TDP) and 200W extra security for the whole PC. Say we have a 105W CPU up to 142W usage and 58W for the remaining PC components. Our PSU needs 470 + 200 + 200 = 870W. In the web, recommendations are 750, 850 or 1000W, depending on how safe we plan.

For 2x RTX 3080 in a PC, a 1200W PSU is the bare minimum and risky for occasional peaks. 1300W seems to be enough (a high TDP CPU suggests 1400W).

However, these are plain consumption calculations. The other PSU consideratons are noise and price. Up to ca. 1200W, prices increase readonably. Above, PSUs become expensive, say, €370 for 1600W. A silent 1600W PSU costs €480.

Each PSU behaves differently. Read noise test diagrams for watt percentages! Some PSUs become load at 50% load, others at 85%. A good PSU is reasonable silent around 50%.

For a PC with 2x 3080, we expect ca. 1000 ~ 1200W load (and go AI should usually create load). So for a still silent PSU, we must choose 1600W 80+_Titanium (such as Corsair) and pay the bill. For a 1x 3080 PC, the expense is significantly lower.

2 graphics cards must have at least one free slot (2.032cm distance) in between. Easy with 3080 FE. Difficult with OEM cards being 2.7 or 2.9 slots thick when dual PCIe 4.0 x16 at x8 speed mainboards set them only 3 slots apart. One can use PCIe riser cables (not cheap, either) and install the cards on the bottom of a case if it is broad enough (19cm exists and might be sufficient). However, the next problem is fixing the cards and their PCI cable slots onto the case bottom while case manufacturers have not forseen such demand...!

If you install in the mainboard slots, getting a stand for 2 cards (and maybe also the heavy CPU cooler) is difficult and must fit into the case given your case coolers. If necessary, build your own stand...

As you can see, building a PC with 2x 3080 is not just more expensive than expected but also difficult.

RTX 3080 FE is €699 if only it were available anywhere in the world. Scalpers and totally under-estimated demand by Nvidia and retailers apparently by the factor 5. The FE is if you want to go cheap and simple but it is somewhat load. If you want silent, get Asus 3080 TUF (the lowest temperatures by far, choose the quiet BIOS by the hardware switch) or MSI 3080 X Trio (even a bit more silent but 10K warmer because of slightly lower RPM). You can't get quieter by usual, very expensive and difficult water-cooling via fans. These two cards (apparently eventually each in the ca. €740 ~ 760 range) are quiet enough, unless you overclock them. Search Youtube for some card and "noise" so you can listen.

Case cooling: use slightly positive flow straight from the front also on the GPU level to the rear! Get a case appropriate for that, not too small, with mesh front and not meant for a silent PC (so that CPU or GPU do not throttle. Read tests from Gamers Nexus. E.g., I consider Phantecs P500A, Fractal Meshify S2 (probably needs other case fans - less silent but enough RPM and air volume, 120m^3/min or 1.7th of that in feet per second) or Cooler Master H500 (yes, without additional letter). Be Quiet is tempting but we must refrain from cooking your chips!

A 1 card PC build amounts to €1500 ~ 1900. A 2 cards build to €2500 ~ 3000.

Have I forgotten anything?

[RobertJasiek]

Here are technical RTX 3080 details to compare Asus TUF to MSI GX3:
https://m.youtube.com/watch?v=3yrTlsgq9s0
Optimum Tech / youtube, video position 6:29 to listen noise,
i9-10900K, Benchtable, 3D load, ambient 21C, micro at 25cm distance:

Code: Select all

Model                C    RPM    dB    W/system

Asus TUF Gaming OC   60   1650   41,6  480
MSI Gaming X Trio    72   1240   38,2  487

[RobertJasiek]

I have continued to explore the possibility of 2x RTX 3080.


2x 3080 air cooled need at least 1 slot free above and below each card.

All well air cooled, dust protected cases are only suitable for 2x 3080 (except maybe Founders Edition) put into the PCIe slots directly. Riser cables to manually built basements, whose fixation is unclear, for the cards are in conflict with case walls.

2x Nvidia RTX 3080 Founders Edition has 2 slots width. Therefore, they fit into mainboards having at least 2 PCIe "x16" slots each with 4.0 x8 (or 3.0 x16, which is typical for Intel-CPU mainboards) speed in dual use and that are 3 slots apart. Such X570, LGA1200 or LGA2066 mainboards are available after the most meticulously careful study of specifications and handbooks (compare my earlier warning) for ca. €270+. (For comparison, a simple B550 mainboard is available for ca. €100 and works for 1 card.) If you can accept the Founders Edition, such a solution works. I consider this card somewhat too loud.

I guess that 2x 3080 water cooled costs at least ca. +€500 ~ €600 (of that >€300 for the cards' cooling in case of self-assembly). If you consider 1x RTX 3090 good enough (although it is only 15 - 20% faster than the 3080), you hardly save money because the card costs €1500.


How about 2x 3080 each with almost 3 slots width? We need a mainboard having at least 2 PCIe "x16" slots each with 4.0 x8 (or 3.0 x16) speed in dual use and that are --- 4 --- slots apart. These current suitable mainboards exist:

Gigabyte X299X AORUS MASTER (rev. 1.0), €380, socket 2066, 48(?) lanes (*1).

MSI Creator-X299, €450, socket 2066, 48 lanes.

MSI MEG X570 Godlike, €580, chipset X570.

Some Supermicro mainboards (*2).

(*1) Beware the X299X spelling! (X299 is a different mainboard.) It is unclear if 2 cards do run each @ x16 speed without activating SLI. The manuals have been written by copy&paste. One should ask the manufacturer if 2 non-SLI cards do run at that speed.

(*2) C9Z490-PG, C9Z490-PGW (chipset Z490); X11SAT (chipset C236). The manuals are hopelessly ambiguous concerning the PCIe slots in which to put 1, 2 or 3 x16 cards. Therefore, I cannot confirm whether a distance of at least 4 slots can be established. Ask the manufacturer.


Intel i9-10900X is a typical LGA2066 / X299 CPU at €530. For AMD AM4 / X570, we can assume a comparable Ryzen 9 3900X (2 cores more, slower clock) at €400.

Hence, let me estimate the excess expense in € for 2 instead 1 RTX 3080 on a cheap AMD B550 mainboard:

Code: Select all

--------------------------------------------------------------------------
AMD     Intel   Item             Details
--------------------------------------------------------------------------
   >+700        2nd RTX 3080
<+480   +410    mainboard/CPU    AMD +0 CPU. Intel +280 mainboard +130 CPU.
    +140        PSU              1500W (Be Quiet) instead of 1200W (Corsair).
--------------------------------------------------------------------------
+1320  +1250                     sum
--------------------------------------------------------------------------
  47%    44%                     fraction of expense for non-GPU items
--------------------------------------------------------------------------

IMO, the extra cost for the mainboard and (in the case of Intel) CPU is too large to justify building a PC with 2x 3080 having a 3-slot design. Financially, the Founders Edition is the only viable option for 2x 3080 and, on an AMD mainboard, maybe even a quality 1200W PSU might be enough. (I can't guarantee this.) For an extra expense of +€700 or 840, one might build such a PC.

I won't because I prefer a quieter and cooler RTX 3080. Saving some money now gives me an easier option to upgrade when Nvidia can use 5nm, 3nm or 2nm in a few years.


Is my analysis reasonable or do you have alternative suggestions of how to build a 2x 3080 3-slot-design PC without spending too much on mainboard and CPU? Note that I have already disregarded an open or bench case build for myself.


EDIT: If you want to build 4x 3080 water cooling this mainboard (with 2 slot distance between x16 speed slots) is available: Gigabyte X299-WU8 (rev. 1.0).

EDIT 2: The problem with current Intel CPUs and chipsets is, besides price, that they are not future-proof without PCIe 4.0. If one wants to build high end Intel, it is better to wait for new Intel CPUs and mainboards with this feature. Although it can be ignored at the moment, spending thousands on a new gaming PC should last for several years. This is uncertain with PCIe 3.0. Only for an industry / business PC, one need not care about much else than stability.

[RobertJasiek]

According to thegamrone / youtube, RTX 3080 is 99% ~ 108% as fast as 2x GTX 1080 TI SLI in 1080p/2160p 3D gaming at Ultra with i9 10900K.

[RobertJasiek]

Correction: For AMD Ryzen 9 3900X at €400, the most comparable Intel LGA2066 CPU seems to be Core i9-10940X at €775. IOW, when choosing LGA2066, one either can feed Intel or selects the slower i9-10900X.

With 10th generation, Intel drastically dropped X-CPU prices but still is far more expensive per clock in the high end and very much more so per watt. If Intel wants to compete with AMD, Intel can't bring 11th generation successors of 10900K and 10900X soon enough together with a further drastic decrement of prices.

[wineandgolover]

IMO, the extra cost for the mainboard and (in the case of Intel) CPU is too large to justify building a PC with 2x 3080 having a 3-slot design. Financially, the Founders Edition is the only viable option for 2x 3080 and, on an AMD mainboard, maybe even a quality 1200W PSU might be enough. (I can't guarantee this.) For an extra expense of +€700 or 840, one might build such a PC.

I won't because I prefer a quieter and cooler RTX 3080. Saving some money now gives me an easier option to upgrade when Nvidia can use 5nm, 3nm or 2nm in a few years.

So Robert, have you talked yourself out of a new rig? There will always be better hardware coming.

Have you considered building a rig that is good enough to beat top pros consistently, but is merely good enough, not the best? I suspect 500 playouts per second will more than meet your needs, and such a machine would save you tons compared to your dream rig.

[RobertJasiek]

I will definitely get at least one 3080 (when supply allows prices to approach MSRPs). As currently I do not have a desktop PC (except for a tiny barebone), I also need to buy all components for it. My intermediate conclusion is only that a PC with 2x 3080 appears to be unrealistic (or else too loud) for me.

Initially, I calculated +€700 for the second card and that would have been feasible. However, having to spend +€1300 results in a total of ca. €3100, which is a bit more change than I am willing to spend:) Especially so since, according to my current understanding, one 3080 can already provide superhuman strength (except for certain ladders etc.), if necessary with some extra thinking time. Combined with new other components (reasonable CPU + RAM), this is all the more possible.

Good enough is good enough and Threadripper, 4x 3080 water cooled is just a dream (for us mere mortals). OC, I will study any reports on deep learning speed of 3080.

[Friday9i]

I'll take one RTX 3080, but I think I'll underclock it to drastically reduce power consumption. And if it works well to reduce heat&power&noise, without huge impact on performance, I may take a 2nd one... We'll see

[RobertJasiek]

I'll take one RTX 3080, but I think I'll underclock it to drastically reduce power consumption. And if it works well to reduce heat&power&noise, without huge impact on performance, I may take a 2nd one... We'll see

Do you mean the Founders Edition?.

It might be easier to simply regulate the fans of Asus TUF or MSI GX3, if some tool allows this. The FE runs at 76C so does not seem to allow much fan regulation.

[Friday9i]

I'll take one RTX 3080, but I think I'll underclock it to drastically reduce power consumption. And if it works well to reduce heat&power&noise, without huge impact on performance, I may take a 2nd one... We'll see

Do you mean the Founders Edition?.

It might be easier to simply regulate the fans of Asus TUF or MSI GX3, if some tool allows this. The FE runs at 76C so does not seem to allow much fan regulation.

I have a Gigabyte 2080 and am happy with it, their Aorus Engine tool allows to easily underclock / overclock the cards, so I'm limiting the power used: it allows me to run it quite cool, with reasonable noise and only 10% to 20% performance reduction. That's the price to pay to keep the computer in the living room without having too many family complaints .

[RobertJasiek]

Gigabyte 2080 is a 2.5 slots card, it seems. Gigabyte 3080 occupies 2.7 slots. Which mainboard do you plan to use for 2 cards?