Brand new 15" Macbook Pro is laggy with 4K Monitor...

Discussion in 'MacBook Pro' started by Molson1020, Feb 13, 2016.

  1. Molson1020 macrumors regular

    Feb 3, 2009
    Hey guys,

    So I just purchased a brand new 2015 15" Macbook Pro (the $2,000 base model), however when I hook it up to my new Dell 27" 4k Monitor, Photoshop become very laggy. If I try and use the brush tool, it takes second to register my strokes with my Wacom Intuos Pro. I have the resolution on the monitor set to 2560x1440 (same as the Thunderbolt display).

    Is there a reason why this is happening?

    Thanks for any help.
  2. size06 macrumors newbie

    Sep 9, 2015
    Do you use the 2560x1400 scaled resolution from the monitor settings, right ? Maybe you should try to setup your macbook and your monitor to the standard resolution. That won't give you the best workspace but performance wise it should improve alot.
  3. pat500000 Suspended


    Jun 3, 2015
    Maybe you shouldn't buy the base model.
  4. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    Yes, IMHO there's two changes to your Mac's accessories you should make to your workflow.

    First, buy a small TB or USB3 SSD - and use it as a scratch disk with PS; your OS drive shouldn't be a scratch disk. Your Mac has a zippy SSD, but it'll bog down with the caching schema built into PS. I've used scratch disks with PS (starting 20+ years ago), AutoCAD (more than 10 years ago), and GIS applications - you'd be surprised how a separate scratch disk will blow away your current set up. Adobe has documentation right on their web site:

    I have no idea why people will use PS without a fast scratch disk. :confused:

    Second, I'll bet my pipe is bigger than your pipe! Read my post here:
    and buy the Accell cable. Your Dell cable has less bandwidth throughput than the Accell cable I listed in my other post, by a big margin. I have a 2012 i7 Mini Server that I occasionally render on - it has 16GB of RAM and the original spinners, along with a LaCie SSD set up as a scratch disk and the linked-to Accell cable - there's 0/zero/nada lag, and I KNOW the graphics in my Mini are pathetic compared to your Mac; you spent $2500 on hardware, and you're using a $2 Dell cable - get a decent cable made by the only cable manufacturer on the planet that makes DP-compliant cables, and they guarantee them for 2 years, too...

    Make those two changes, and we'll never have to deal with this ever again! :D
  5. Ries macrumors 68020

    Apr 21, 2007
    I call ******** on your cable. All display port cables should be fine, except those labeled as RBR (they only go to 1080P and are for projectors). There is no such thing as a "DisplayPort 1.2" cable, all standard DisplayPort cables support RBR, HBR (High Bit Rate), and HBR2 (High Bit Rate 2), which can support 4K at 60Hz, or up to four 1080p displays using multi-stream.

    Just make sure the cable is DisplayPort certified.
  6. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    And you'd make that call how? By making the same mistake I did by reading "stuff" on the internet? No offense, but I bought two just to try out after "lag" and "stutter" and "overheating" were just some of the words we used every day in my offices, no complaints from my gallery for 2 months now, not one.

    Read posts by others that gripe about lag - none of our Macs or Win PCs lag. Read others post about overheating machines or "sleep issues" - our PCs and Macs run cooler (I run iStat Menus, so I can empirically compare before and after the switch). All of the other DP cables we've used return power on Pin 20, but Apple's TB cable (DP 1.1a compliant) and Accell's DP cables (DP 1.1a or 1.2 compliant) do not return power on Pin 20 - please, Google it for yourself. I used my multimeter on my cables, empirically backing the manufacturer's statements.

    Read about my earlier posts and those of others in the Dell P2715Q thread about using SwitchResX and EDID hacks to get that, and the Dell P2415Q displays working well. I had to clean install OS X on my Mac a couple of months ago, and did not install either of these hacks, simply connected the two Dells to my Mac with the Accell cables and it just worked, and I can see color profiles and resolutions in the Displays Pref Pane now that I needed a hack and utility to get them to work. My Macs and my PCs now correctly read the EDID of the Dells, the BenQs, and the Eizos we're using - we're not running any more hacks or utilities to get our displays to work with our computers.

    And, maybe you didn't know that the per-channel throughput of the Accell cable is greater than those cheaper "compatible" cables. Checked on our PCs.

    You're entitled to your opinion. I don't care, we're using Accell cables now for our displays, and my techs could tell the difference - I did a blind test with 5 of them and all noticed a difference in performance. There's a big difference, to me, between the words "compatible", "certified", and "compliant". Buy one from Amazon, they've got a great return policy... I'm happy with my purchases. I'm not defending Accell, but I'm a happy customer.
  7. Ries macrumors 68020

    Apr 21, 2007
    It is not an opinion, it is fact. It's says so on the page who manages and made the standard.
  8. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    Nice call. I think it's marketing BS. I read the specification and and continued to their Product portal, not relying weakly on the marketing crap. I read about issues with power return over Pin 20 going back years. Keep digging on that site... I'll wait.

    OK, long enough. Go to that site's Products portal. Select "Cables". You'll find that the only cable manufacturer that supports DP 1.2 AND up to 2160p is Accell. Every other manufacturer on the site you called out supports up to 1080p/1440p/1600p - I checked before buying.
  9. kerochan macrumors newbie


    Dec 14, 2015
    Base model is still powerful machine, I think its best to as Apple direct, there will be an answer. No reason that anything should run slow on a new MBPro
  10. ncrypt macrumors 6502

    May 16, 2012
    @Molson1020 , did you manage to resolve this. I have the same issue with my Iris Pro rMBP.

    @campyguy , the Accell cable is on order ;)

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