When we made our “how air coolers work” video, a lot of viewers were interested in the inner workings of copper heatpipes and their various means of facilitating capillary action. Today, we’re revisiting our TLDR series with a video on how closed-loop liquid coolers work. We’ll be talking about permeation, air pockets, stators, impellers, coldplates, and chemical composition of the coolant.

This content has custom-made animations that we rendered specifically for explanation of how CLCs work. GN’s Andrew Coleman modeled and animated a closed-loop cooler for the piece, referencing NZXT’s Kraken X52. Because of the level of detail and custom animations of this content, NZXT sponsored GN to put this piece together. The content applies to all liquid coolers, but particularly focuses on closed-loop products; all concepts herein can be applied to CLCs across the industry from various suppliers and manufacturers. Our technical deep-dive for today serves as a means to fully detail liquid cooling and how it works, drilling down to piano-wire granularity (literally).

With days to go before we fly out to Taipei, Taiwan for this year's Computex show, EVGA's new 1080 Ti SC2 Hybrid card arrived for tear-down and analysis. We might not have time to get the review dialed-in on this one before the show, but we figured the least we could do is our inaugural disassembly of the card.

EVGA's 1080 Ti SC2 Hybrid makes a few changes over previous Hybrid cards, as it seems the liquid+air amalgams have grown in popularity over the past few generations. Immediately of note, the shroud now carries some 'tessellation' paint embellishments, an illuminated name plate, and a cable tether for the radiator fan. Small increments.

The EVGA GTX 1080 Ti FTW3 is the company’s attempt at a 3-fan cooler, entering EVGA into the three-fan ranks alongside ASUS, Gigabyte, and MSI. The difference with EVGA’s card, though, is that it’s a two-slot design; board partners have gone with a “bigger is better” mentality for the 1080 Ti, and it’s not necessarily advantageous. Sure, there are benefits – taller cards mean taller fans, like on the Gaming X, which results in slower rotation of fans without sacrificing volume of air moved. It follows then that taller fans on taller cards could be profiled to run quieter, without necessarily sacrificing thermal performance of the GPU, VRM, and VRAM components.

But we’re testing today to see how all that plays out in reality. In our EVGA GTX 1080 Ti FTW3 review, we benchmark the card vs. EVGA’s own SC2, MSI’s 1080 Ti Gaming X, Gigabyte’s Xtreme Aorus, and the Founders Edition card. Each of these also has an individual review posted, if you’re looking for break-outs on any one device. See the following links for those (listed in order of publication):

It’s Not About Gaming Performance

Having reviewed this many cards in the past few weeks, it should be apparent to everyone that same-GPU cards aren’t really differentiated by gaming performance. Gaming performance is going to be within a few percentage points of all devices, no matter what, because they’re ultimately governed by the GPU. A manufacturer can throw the world’s best PCB, VRM, and cooler together, and it’s still going to hit a Pascal wall of voltage and power budget. Further, chip quality dictates performance in greater ways than PCB or VRM will. We have duplicates of most of our cards, and they can perform 1-3% apart from one another, depending on which boosts higher out-of-box.

GN resident overclocker ‘Buildzoid’ just finished digging through the details of EVGA’s GTX 1080 Ti FTW3 ($780) video card, noting that the card is one of the most overbuilt 1080 Tis that we’ve seen yet. The FTW3 over-engineers its VRM and power delivery solution and cooling solution equally, the latter of which we detailed in our 1080 Ti FTW3 tear-down a few days ago.

Much of this is to do with the FTW VRM discussion of last year, something we closed the book on in November. Our conclusion was that the cards were operating within thermal spec, but that there were supply-side QA issues that happened to fall on EVGA. The engineering team decided to design for this by over-engineering every aspect of the VRM on the new ICX and 1080 Ti cards, something we see in today’s PCB analysis:

Our GTX 1080 Ti SC2 review was met with several comments (on YouTube, at least) asking where the FTW3 coverage was. Turns out, EVGA didn’t even have those cards until two days ago, and we had ours overnighted the same day. We’ve got initial testing under way, but wanted to share the tear-down process early to spoil some of the board. This tear-down of the EVGA GTX 1080 Ti FTW3 ($780) exposes the PCB and VRM design, fan header placement, and cooler design for the FTW3. We’re working with GN resident overclocker ‘Buildzoid’ for a full PCB + VRM analysis in the coming days, but have preliminary information at the ready.

EVGA’s 1080 Ti FTW3 is one of the most overbuilt PCBs we’ve seen in recent history. As stated in our SC2 review, the EVGA team has gone absolutely mental with thermal pad placement (following last year’s incident), and that’s carried over to the FTW3. But it’s more than just thermal pads (on literally every component, even those that have no business being cooled), it’s also the VRM design. This is a 10+2 phase card with doubling and dual FETs all across the board, using Alpha Omega Semiconductor E6930s for all the FETs. We’ll save the rest of the PCB + VRM discussion (including amperage and thermal capabilities) for Buildzoid’s deep-dive, which we highly encourage watching. That’ll go live within a few days.

EVGA’s GTX 1080 Ti SC2 ($720) card uses the same ICX cooler that we reviewed back in February, where we intensely detailed how the new solution works (including information on the negative type thermistors and accuracy validation of those sensors). To get caught-up on ICX, we’d strongly recommend reading the first page of that review, and then maybe checking the thermal analysis for A/B testing versus ACX in an identical environment. As a fun add, we’re also A/B testing the faceplate – it’s got all those holes in it, so we thought we’d close them off and see if they actually help with cooling.

The fast version is basically this: EVGA, responding to concerns about ACX last year, decided to fully reinvent its flagship cooler to better monitor and cool power components in addition to the GPU component. The company did this by introducing NTC thermistors to its PCB, used for measuring GPU backside temperature (rather useless in a vacuum, but more of a validation thing when considering last year’s backplate testing), memory temperature, and power component temperature. There are thermistors placed adjacent to 5 MOSFETs, 3 memory modules, and the GPU backside. The thermistors are not embedded in the package, but placed close enough to get an accurate reading for thermals in each potential hotspot. We previously validated these thermistors versus our own thermocouples, finding that EVGA’s readings were accurate to reality.

Although this is absolutely a unique, innovative approach to GPU cooling – no one else does it, after all – we found its usefulness to primarily be relegated to noise output. After all, a dual-fan ACX cooler was already enough to keep the GPU cool (and FETs, with the help of some thermal pads), and ICX is still a dual-fan cooler. The ICX sensors primarily add a toy for enthusiasts to play with, as it won’t improve gaming performance in any meaningful way, though those enthusiasts could benefit from fine-tuning the fan curve to reduce VRM fan speeds. This would benefit in noise levels, as the VRM fan doesn’t need to spin all that fast (FETs can take ~125C heat before they start losing efficiency in any meaningful way), and so the GPU + VRM fans can spin asynchronously to help with the noise profile. Out of box, EVGA’s fan curve is a bit aggressive, we think – but we’ll talk about that later.

Our review of the nVidia GTX 1080 Ti Founders Edition card went live earlier this morning, largely receiving praise for jaunts in performance while remaining the subject of criticism from a thermal standpoint. As we've often done, we decided to fix it. Modding the GTX 1080 Ti will bring our card up to higher native clock-rates by eliminating the thermal limitation, and can be done with the help of an EVGA Hybrid kit and a reference design. We've got both, and started the project prior to departing for PAX East this weekend.

This is part 1, the tear-down. As the content is being published, we are already on-site in Boston for the event, so part 2 will not see light until early next week. We hope to finalize our data on VRM/FET and GPU temperatures (related to clock speed) immediately following PAX East. These projects are always exciting, as they help us learn more about how a GPU behaves. We did similar projects for the RX 480 and GTX 1080 at launch last year.

Here's part 1:

GPU diode is a bad means for controlling fan RPM, at this point; it’s not an indicator of total board performance by any stretch of use. GPUs have become efficient enough that GPU-governed PWM for fans means lower RPMs, which means less noise – a good thing – but also worsened performance on the still-hot VRMs. We have been talking about this for a while now, most recently in our in-depth EVGA VRM analysis during the Great Thermal Pad Fracas of 2016. That analysis showed that the thermals were largely a non-issue, but not totally inexcusable. EVGA’s subsequent VBIOS update and thermal pad mods were sufficient to resolve any concern that lingered, though if you’re curious to learn more about that, it’s really worth just checking out the original post.

VBIOS updates and thermal pad mods were not EVGA’s only response to this. Internally, the company set forth to design a new PCB+cooler combination that would better detect high heat operation on non-GPU components, and would further protect said components with a 10A fuse.

In our testing today, we’ll be fully analyzing the efficacy of EVGA’s new “ICX” cooler design, to coexist with the long-standing ACX cooler. In our thermal analysis and review of the EVGA GTX 1080 FTW2 (~$630) & SC2 ICX cards (~$590), we’ll compare ACX vs. ICX coolers on the same card, MOSFET & VRAM temperatures with thermocouples and NTC thermistors, and individual cooler component performance. This includes analysis down to the impact the new backplate makes, among other tests.

Of note: There will be no FPS benchmarks for this review. All ICX cards with SC2 and FTW2 suffixes ship at the exact same base/boost clock-rates as their preceding SC & FTW counterparts. This means that FPS will only be governed by GPU Boost 3.0; that is to say, any FPS difference seen between an EVGA GTX 1080 FTW & EVGA GTX 1080 FTW2 will be entirely resultant of uncontrollable (in test) manufacturing differences at the GPU-level. Such differences will be within a percentage point or two, and are, again, not a result of the ICX cooler. Our efforts are therefore better spent on the only thing that matters with this redesign: Cooling performance and noise. Gaming performance remains the same, barring any thermal throttle scenarios – and those aren’t a concern here, as you’ll see.

EVGA’s CLC 120 cooler fell on our bench shortly after the EVGA CLC 280 ($130), which we reviewed last week against the NZXT X62 & Corsair H115i. The EVGA CLC 120 prices itself at $90, making it competitive with other RGB-illuminated coolers, but perhaps a bit steep in comparison to the cheaper 120mm AIOs on the market. Regardless, 120mm territory is where air coolers start to claw back their value in performance-to-dollar; EVGA’s chosen a tough market to debut a low-end cooler, despite the exceptionally strong positioning of their CLC 280 (as stated in our review).

Before diving in to this review, you may want to read the EVGA CLC 280 review, NZXT Kraken X42/X52/X62 review, or its subsequent tear-down.

EVGA’s closed-loop liquid cooler, named “Closed-Loop Liquid Cooler,” will begin shipping this month in 280mm and 120mm variants. We’ve fully benchmarked the new EVGA CLC 280mm versus NZXT’s Kraken X62 & Corsair’s H115iV2 280mm coolers, including temperature and noise testing. The EVGA CLC 280, like both of these primary competitors, is built atop Asetek’s Gen5 pump technology and primarily differentiates itself in the usual ways: Fan design and pump plate/LED design. We first discussed the new EVGA CLCs at CES last month (where we also detailed the new ICX coolers), including some early criticism of the software’s functionality, but EVGA made several improvements prior to our receipt of the review product.

The EVGA CLC 280 enters the market at $130 MSRP, partnered with the EVGA CLC 120 at $90 MSRP. For frame of reference, the competing-sized NZXT Kraken X62 is priced at ~$160, with the Corsair H115i priced at ~$120. Note that we also have A/B cowling tests toward the bottom for performance analysis of the unique fan design.

Relatedly, we would strongly recommend reading our Kraken X42, X52, & X62 review for further background on the competition. 

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