Why not get a modern (Haswell or later) Intel CPU and a motherboard with DisplayPort output? You don't need a discrete GPU unless you're MLing or gaming, and you can splurge a bit and get something with DDR4 and/or NVMe. Having faster IO is the best way to make "productivity" software like spreadsheets and editors faster.

== gratuitous shilling below ==

For Christmas I got a new CPU/motherboard combo with a Samsung 960 EVO SSD, and it's ludicrously fast, decently cheap, and a noticeable improvement over my old (heh) SATA SSD.

http://www.samsung.com/semiconductor/minisite/ssd/product/co...