I was thinking about performance today as I converted 250 photos, about 5GB out of Lightroom down to 2MB size and then onto OneDrive. It was only using 5.5G of RAM to do this and I haven't seen my computer use more than 8G RAM while using Lightroom and Photoshop. It did it in no time but having a hex core i7 -5820 desktop overclocked to 4GHz probably helped...LOL
I think that the Surface 3 is capable of doing this but obviously very slowly. At least it doesn't get hot like the SP3 would.
I'm just making the point. Desktops still rule for doing big jobs. I could do this on my Surface Pro 3 but would only consider it if my desktop was not available such as when on holiday and I had a lot of photos to do.
The Surface 3 with 4G is I would think just fine. The complaints on the forum are it would be nice to have Core M and nice to have an SSD, as eMMC speeds are a tiny fraction of what an SSD/PCIe device is capable of. I personally don't think 8G would make that much difference as the performance is severely limited in other ways and Windows works well in 4G even with programs such as Lightroom.
Well under $1000 will buy the Lenovo Yoga 3 11 inch but it isn't a Surface, isn't as compact and the build quality, while high, is not quite as good. It does, however, have the Core M (although it severely throttles on sustained tasks) and a very fast M.2 SSD.
The Surface 3 is unique though if you take into account the supreme build quality and compactness. It remains to be seen with the Surface 4 in a year's time or likely the SP4 at the end of the year will deliver it all. There is no perfect device.