Custom PC - UK (2020-06)

FEATURE / ANALYSIS

flickered a lot for the first few seconds when
using the RTX 2080 Super SLI setup with
ray tracing, affecting scaling performance. It
didn’t do this on the RTX 2080 Ti setup.
We sometimes saw the same flickering
when starting Red Dead Redemption 2 with
both setups as well, and had to run this test
a number of times to get reliably repeatable
results. We naively thought that SLI might be a
mature and largely problem-free technology
by now, but with declining interest from game
developers (and Nvidia to an extent too), there's
still plenty of problems. Be warned that if you do
go down the SLI route, you'll have to put up with
some compatibility issues, as well as faffing with
graphics settings, drivers and profiles.

Performanceandscaling
So,whenit doeswork,is SLIanygood?Let’s
startwiththegoodnews, whichis thatwhen
youhavea gameanddriverthatproperly
supportsSLI,theperformanceandscalingis
superb.Wesawthisin ShadowoftheTomb
RaiderwhenusingtheRTX 2080 Ti SLIsetup.
With 97 percentscalingat2,560x 1,440,we
sawanaverageframerateof211fps,anda
164fpsminimum– superbresultsthatcould
enableyoutorunthisgameata super-high
refreshrateif yourmonitorsupportsit.
Enablingray-tracedshadows(attheHigh
setting)alsoresultedin smoothperformanceat
2,560x 1,440,witha 120fpsaverageand80fps
minimum– scaling 76 percentoverusinga
singlecard.Youcouldevenrunthegameat4K
withthesesettings,withtheRTX 2080 Ti SLI
rigneverdroppingbelow45fps,comparedto
a 24fpsminimumwitha singlecard.
Aswementionedearlier,theRTX 2080
Superhadproblemsin thisgame,butit worked
fineonceyougotpasttheinitialfewseconds
offlickering.AnRTX 2080 SuperSLIsetup
can’treallycopewithhighraytracingat4K,but

it candoit wellat2,560x 1,440(witha 67fps

minimum).Thissetuphadthesame67fps

minimumat4Kwithoutraytracingtoo.

Whiletheseresultsaren’tproblem-free,they

showthepotentialforSLIwhenit workswell.If

youwantalltheray-tracedeyecandyturnedon

at4K,anRTX 2080 Ti SLIsetupis prettymuch

theonlywaytoachieveit atthemoment.

Mostoftheothergameswetesteddidn’t

scaleanywhereneartothe 97 percentwe

sawinShadowoftheTombRaider,butSLI

usuallyhadatleastsomebenefit.Forthis

feature,wealsotestedsomeoldergames,so

wecouldgeta largerpictureofSLIsupport,

andtoseeif wecouldfinallyturnupevery

singlegraphicssettingonthesegamesnow.

Oneexampleis TheWitcher3,whichwe

testedatUltrasettingswithNvidiaHairWorks

maxedout.Runningthisgameat4Kshowed

reasonablescalingwithSLI,showinga 67

percentaverageframerateincreasewiththe

RTX 2080 TiSLIsetup,and 70 percentwith

theRTX 2080 Supercards.Onitsown,an

RTX 2080 Superdropsdownto49fpsinthis

gameat4K,whichis perfectlyplayable,but

thisminimumgoesrightupto84fpswhen

youadda secondcard.

WealsotriedoutDeusEx:MankindDivided

onUltrasettingsforthesamereason.Wedidn’t

havehighhopesforbigSLIperformancein

thisgame,asit’sanAMDGamingEvolvedtitle,

andsureenough,theSLIscalingwaspretty

uninspiring,particularlyat2,560x 1,440.At

4K,theresultswerea bitbetter,withtheRTX

2080 Ti SLIsetupaveraging72fpswitha 58fps

minimum,comparedtoa 48fpsaveragewith

onecard.Addinga secondRTX 2080 Superalso

makesthisgameproperlyplayable,takingthe

minimumfrom33fpsto45fps.Thescalingmight

notbehuge,butthere’sstilla definitebenefit.

Backtothenewergames,RedDead

Redemption2 wouldn’tscale withSLIatallin

DirectXmode,butit scaleda bitwithVulkan.

Therewasn’tmuchdifferencebetweenthe

99thpercentileframerateshere,butaddinga

secondcarddidboosttheaverageframeratea

fairbit,withscalingvaryingfrom40-48percent.

Scalingin TotalWar:WarhammerII at2,560

x 1,440wasbarelyworthmentioningeither,

particularlyontheRTX 2080 Ti SLIsetup.

Although,tobefair,a singlecardalready

averages94fpsin thisgame,whichis plenty

fora strategygame.Wesawbetterscalingin

thisgameat4K,withSLIbringingtheminimum

frameratesabove60fpsonbothsetups.

Noiseandpower

Asidefromcompatibilityissues,theothermain

concernsarepowerdrawandnoise.Withtwo

cardsrunningatfullpelt,theScanmachine

madeanawfullotofnoise.It’snotjustthatyou

havefansfromtwographicscardsmaking

noise,buttherealsoisn’tmuchroomforthe

fanstodrawairthroughtheircoolers.

Evenwitha slotspacebetweenthem,there’s

stilllittleroomforthecardstobreathe,andthe

secondcardendsupbeingquiteclosetothe

PSUshroudtoo.TheScanwassignificantly

quieterwithjustoneofeithercardinstalled

(muchquieterthanyouwouldnormallyexpect),

asthefansdon’thavetoworkashardtodraw

airintothecooler.

You can use ProfileInspector to create custom SLI profiles and optimise SLI performance, as well as force

some non-SLI games to support it

You’ll want a hefty PSU for an SLI build, such as this
850W Corsair model