Hello Greg
I have been running my MB1 with an external computer for a long time now. This was to facilitate JTDX with maximum decode cycles without delays to the start of TXing. I could not achieve that with the MB1 even with the upgraded CPU, RAM and SSD.
The external computer is Ryzen 5800X with a Radeon 5600XT graphics card which, as you may do, I built myself.
PROS: The difference in computer speed is enormous. Graphics, your main concern, is not noticeably visually different but of course it is not taking CPU resources as it does with the on-board chip in the MB1. There are no lags, visual glitches in ESDR2 or noise artefacts in the MB1 on SSB and CW. It is easy to connect the MB1 - just use an ethernet cable and set the computer ethernet port IP accordingly.
CONS: The eCoder is useful because the front panel functions of the MB1 are lost in this configuration. Therefore without it, you would go from SDR with knobs to SDR without knobs and have to use the software exclusively. Of course you can do that, it is no different to having the SunSDR DX for example but a bit of a waste for the MB1.
I daresay each individual's liking or otherwise to using the MB1 with an external computer will vary. If you will want to build up a machine regardless, I would say to try it. Personally, I would not now revert to using JTDX on the MB1 - what was high spec in 2016 cannot cope with the digital mode and software advances of the past 3 years if you want to be DXing and need the ultimate performance. For casual digital operating, the MB1 on its own is adequate. Operating CW split pile up working, for me anyway, took some getting used to without the convenience of the MB1 front panel controls at my disposal.
Erik.