Swiftech MCP35X2 Pump

Posted: January 29, 2012 in Pumps
Tags: , , , ,


Welcome to my Swiftech MCP35X2 review, possibly the ultimate in “Smart PWM Monster Pumping Performance”. After reviewing the Swiftech 35X single pump, I found myself making room for the powerful smart pump as part of my daily use and CPU block testing rig.  While manual speed control pumps move water fine, they can not be controlled automatically without more advanced (and expensive) controllers.  PWM controlled pumps offer a larger operating range and can be controlled with nothing more than a motherboard CPU header.  Just before CES 2012, Swiftech announced an arsenal of exciting new and innovative products, one of which was taking the previous flagship 35X success and marrying it together in a package of two (The MCP35X2). Two pumps in series provides nearly double the head pressure and also adds the pump redundancy safety benefit if one pump stops working. When Swiftech asked if I’d be interested in reviewing, I was happy to accept as I thought it would also make the perfect test pump for my new radiator test bench having all that range, power, and precision(easily repeatable) PWM control.

I would like to give special thanks to Gabe from Swiftech for providing this product review sample:

That’s a lot of smart PWM pumping power in the palm of your hand.

Before digging into the review, let’s first have a look at the product specifications and notes from Swiftech’s site:

  • Small Footprint: L4.9″ x W2.8″ x H1.6″ (L126 x W72 x H41mm);
  • 50,000 hours MTBF (Mean Time Between Failure) ;
  • 12 Volts DC convenience: plugs into the computer power supply
  • Variable speed control via PWM thru the motherboard, from 1300 rpm for completely silent operation, to 4500 rpm for ultra high flow performance;
  • Simultaneous pump speed control using one PWM motherboard header is achieved using the included PWM splitter cable.
  • Superior head pressure and flow rate (in the useable range) to any pump in its footprint: the X2 features twice the head pressure as the MCP35X.
  • G1/4″ ports standard for compatibility with a large assortment of fittings;
  • No maintenance when used with distilled water, and anti-fungal additives (our HydrX additive is recommended);
  • Quick installation with adhesive neoprene pad, or permanent installation with supplied hardware;
  • Optional “built-in” MCP35X-Res reservoir;
  • Ready for upcoming 5 1/4″ bay reservoir solutions by Swiftech.
  • 2 year warranty
Product Description
The MCP35X2 is the dual motor version of Swiftech’s flagship MCP35X pump. The product is designed to provide extreme flow rates in loops that include multiple devices, for example multiple radiators and triple or quad SLI/Crossfire liquid cooled graphics cards; pump redundancy also provides maximum safety in mission critical systems: if one pump fails, flow will continue to circulate thru the system thanks to the second pump. The unit features:
  • The MCP35X2-H dual pump housing:
    • designed to provide considerably enhanced hydraulic performance;
    • compatible with multiple tubing options thanks to the G1/4 port standard;
    • compatible with the optional MCP35X-Res reservoir;
    • available in two colors; classic black or fashionable white
    • also sold separately, and compatible with all MCP35 series pumps
  • Two MCP35X pump motors:
    • 12VDC and PWM controlled, allowing variable speed control thru the motherboard from 1300 to 4500 rpm, and linked with Swiftech’s PWM splitter cable for simultaneous pump speed adjustments using only one PWM motherboard header.
Technical Specifications
Motor type 2x Electronically commutated, brushless DC, spherical motors
Nominal voltage 12 V DC
Operating voltage range 9 to 13.4 VDC
Max. nominal power (@12 V) 18 W x 2
Max. nominal current (@12 V) 1.5 A x 2
Max. nominal head (@12 V) 27.9 ft (8.5m)
Max nominal discharge (@12 V) ~ 4.17 GPM (15.8 LPM)
Maximum pressure 22 PSI (1.5 BAR)
Temperature range Up to 140 °F (60 °C)
Electrical power connector 2x Molex 4 pin
PWM + RPM Signals 2x 4-pin connector
RoHS Compliant
Port thread standard G1/4
MTBF 50,000 Hours
Weight 15 oz
Dimensions (not including fittings) L4.9″ x W2.8″ x H1.6″ (L126 x W72 x H41mm)
That’s a lot of goodness and technical information to absorb that I’ll work on going over as I complete the review.

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  1. Tingez says:

    You just made my mind up on what pump/s system to get for my own personal rig. As well as the pumps i will be recommending in my shop. I love this pump setup. Swiftech have done a really good job with this product and for that matter the single unit system too.

  2. Elke says:

    e, jednakowoż teraz
    przyjechało mocne pociągnięcie. Elke Zamknięcie sznurka
    wyskoczył w dłoni, zniknął w zaroślach. Huk tratowanych
    flor roslinnych,
    skończony potężnym beknięciem. Wcześniej po wszystkim.

  3. Gadgety says:

    Hey Martin. I’m putting together my first water cooled computer and since the basement ambience is 5-15 degrees celsius cooler (depending on time of year), I’m planning to put a remote radiator there. The extra length of tubing will be about 8-10 feet round trip.This dual pump will come in handy with its extra head. The temp advantage, and noise isolation makes it appropriate to have the pump by the radiator and keep all noise out of my home office. I haven’t got everything figured out yet, for example – I’d like to keep the reservoir at the highest point to enable air bubbles to exit there, rather than by the pump/radator. I still don’t know how to handle cabling, and placing the pump remotely will complicate the PWM controlling off the motherboard+the 12V power supply. I’m not totally clear as to what it will mean in terms of maintenance either (i.e. opening loops, running up and down the stairs etc). Any suggestions, or warnings are welcome.

    • Martinm210 says:

      I have seen it done before. My only suggestion is to use larger ID tubing as the length does start adding some restriction. A nice large reservoir would make filling easier too. I would probably place it right before the pump. It’s a good setup that way. Been done before.

  4. Michael says:

    Question: Would you recommend two swiftechs 35x with a single top connected with a tube to avoid vibrations or would you recommend a dual top like for example the EK-DDC Dual TOP V.2 G1/4 – Black Acetal?

    • Martinm210 says:

      I think either option works fine. Dual top is just more compact and cleaner looking.

      • Michael says:

        I have another question: is there any advantage of using a different pump top for Swiftech Extreme Flow Dual 12v DC Pump like the EK Water Blocks EK-DDC Dual TOP V.2 G1/4 instead of the original dual pump top of swiftech or is it just for aesthetics?

        • Martinm210 says:

          Mostly aesthetics, it’s a pretty optimized top already. I found the 35x top and xspc tops to be pretty close depending on the barb used so I assume the same is true for the dual top.

  5. Louis says:

    Hello Martin,
    I am studying engineering and am working on an independent project which requires and adjustable flow rate pump. I purchased one of these as a possible option. I was wondering whether you know if there is a minimum frequency at which they will accept pwm input?

    Also I have run into an issue which could be a known issue or could be one of those dud pump issues. I have noticed that even with pwm turned off, my pump tends to have a high flow rate initial spurt and then drop down to an extremely low flowrate. Is there anything you can think of which would account for this, or did I get a dud?


  6. Anthony says:

    MOBO: Asus p9x79 Pro
    CPU: i7 3820
    RAM: 8gb G-Skill Rip jaws Z 2133
    video: 2 x HIS Radeon HD 7970(Crossfire)
    SSD: 2 x Samsung 840 Pro SSD (Raid 0)

    Water cooling parts
    2 x Coolgate quad 120mm Radiator
    XSPC RayStorm
    2 x Swiftech Komodo 7970 full cover. (in series)
    Alphacool vp655 vario pump(d5)
    EK x-top for pump
    primochill 1/2in rigid tubing

    My idle CPU is stead 34c while the GPUs idles at 41c. The GPUs spike to mid to high 60c, have seen them close to 70c when playing games and they cards are not at full load.. My ambient temps are normally around 25c – 26c. The idles are a bit high but I think that its due to the higher ambient. But the load temps seem to be too high. Could this just be a flow issue? Is a single D5 not enough to pump this loop?

    I am thinking it is the pump setup and was thinking about using the MCP35x2. What do you think of this?

    • Gadgety says:

      I’m looking into the MCP35x2 as well, but I’m concerned what happens if one of the pumps inside the housing breaks. Do I have to get an entire 35×2 unit then? In that case, better to go with dual MCP35x pumps in separate housings instead.

      • Anthony says:

        Well you would run dual pumps for added pressure. This pump is just 2 mcp35x’s. So if one breaks down the other will continue and keep the loop flowing. That means you would have to buy and install a new mcp35x2. Since the unit is sold as one, the warranty would be void if you take one pump of four replacement.

    • Louis says:

      I am not an expert on computer cooling loops, but looking at specs for pump, the mcp35x2 does not have a higher flow rate so much as a higher pump pressure. So if you are noticing that the maximum flow rate you are getting through the system is very low, then you probably are loosing a lot of the pumps energy to drag and pressure drops and a higher pressure pump system will do the trick. If you are noticing that you get pumps full flow rate in the system, but system is still running hot, then you probably will need to add more radiators or more fluid.

  7. JackNaylorPE says:

    Anyone know the dimensions of this thing mounted on the pump specific 35X2-HS heat sink. All the US sales sites, swiftech site, nada.

  8. Judelexan says:

    Thanks for this great review; I’ve actually been eyeing this pump for a new build. Reading your site for a few weeks has increased my knowledge immeasurably, and prevented me from making some very costly mistakes.

    Now, on to making some *different* costly mistakes 🙂

  9. JackNaylorPE says:

    Question if I may Martin….. I took the lower HD cage outta the Phanteks Enthoo and have the 35×2 there (under the top 3) which gives me a height restriction….. been arguing with myself between the following choices ….. 90 elbow into “optimal inlet or 45 elbow to “alternate” inlet ?

    • Martinm210 says:

      90 into optimal would probably have a very slight edge since an external elbow is fairly large in ID and the distance is pretty far away, The alternate inlets are generally a pretty small ID within close proximity of the impeller causing the flow into the impeller to be less uniform. That’s a powerful pump with plenty of head to spare though so either would work just fine.

      • JackNaylorPE says:

        That was what i was going to do if I didn’t her from ya before firing it up 🙂

        I’m getting a bit concerned about the powerful part a start up day nears 🙂 …. my 1st rigid acrylic build and the “pushing in” was easier than I expected. I did use short (2.5″ on outlet / 3.5″ on inlet from res) flex tube compression connections on inlet and outlet of pump in an attempt to minimize vibrations……

        Wish there was a way to tone it down on start up….. planning to run at 40-50% PWM but gotta start it up and get into BIOS first 🙂 …. hmmmm…. see any harm in filling loop and testing with just one pump powered ?…. setting the BIOS to 50% max and then shut down, rinse and repeat ?

  10. JackNaylorPE says:

    Well just wanted to let ya know all up and running …. have 4.6 Ghz at 1.38 VID and temps all under 75C …. only issue is can’t get M6F to tone down the speed …. lowest I have seen is 2800ish but mostky above 3050 rpm at idle (CPU temp = 26C). FanXpert2 “says” I’m at 38% PWM but rpm of 3040 is more like 68% .

    • Judelexan says:

      While I haven’t used the Asus software, I had a similar problem with the Gigabyte software on my board. Just set it to the lowest you can (so you don’t end up rocketing too much air into your loop at startup and have SpeedFan take over at log in.

      • JackNaylorPE says:

        Well got it “Golden” now ….. instead of trying to “control” how FanXpert2 does it, I let FanXpert2 do it’s thing and ran the tuning protocol….. worked like a charm ….. I’m now running a custom profile that gives me:

        13% PWM @ 0C
        13% PWM @ 20C
        20% PWM @ 50C
        75% PWM @ 70C
        100% PWM @ > 70C

        CHA fans (rads) are running at :

        0% PWM @ 0C (off)
        0% PWM @ 20C (off)
        32% PWM @ 45C
        92% PWM @ 72C
        100% PWM @ > 72C

        Weird things is …. in FanXpert’s test, it\ recorded the following pump speeds.

        0% PWM = 1230 rpm
        10% = 1243
        20% = 2477
        30% = 3824
        40% = 4485
        50% = 4470
        60% = 4485
        70% = 4440
        80% = 4470
        90% = 4485
        100% = 4488

        • Judelexan says:

          My results with SpeedFan are identical… odd that there is such a tight range

          • JackNaylorPE says:

            SpeedFan won’t work with the Maximus VI Formula 😦

            I don’t think it’s accurate as in practice I see a much wider range of rpms as reported by AiSuite 3

            I have reprogrammed it tho ….

            13% PWM @ 30C
            25% PWM @ 35C
            40% PWM @ 40C

            That pretty much caps me at 30% PWM at 50C and keeps pump speeds in nice quite range as GPU goes from 40-45C