Homebuilt computer has slowed noticably.... why?

My home built is getting a bit old, but within the last weeks has
noticable slowed in many operations. For example, in Photoshop, using
the erasure tool; before, erasures were instanteous. Erased materal
instantly disappeared from the scene. Now, it sometimes disappears,
and sometimes the dissappearance lags the erasure in what seems an
erernity, but is probably a second or so. The same lag appears in
simple operations in other programs as well, Thumbs up, my program for
cataloging images, and Rootsmagic, my genealogy program.

Here's my system. I'm guessing it has to do with the Intel microcode
"fixes". If so, is there any way to improve performance? Perhaps a
more modern processor? If it's the microcode, can the fix be removed?

Windows 10 Pro ver 1803 Latest update KB4100347 included the Intel
microcode fixes (8/26/2018)


EVGA GeForce GTX 960 04G-P4-3962-KR 4GB SC GAMING (8/7/2015)

Intel Core i5-4690K Devil's Canyon Quad-Core 3.5 GHz LGA 1150 88W
BX80646I54690K Desktop Processor Intel HD Graphics 4600 (7/10/2015)

GIGABYTE GA-Z97X-UD3H-BK (rev. 1.0) LGA 1150 Intel Z97 HDMI SATA 6Gb/s
USB 3.0 ATX Intel Motherboard (7/10/2015)

G.SKILL Ripjaws X Series 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 1600
(PC3 12800) Desktop Memory Model F3-1600C9D-16GXM (7/10/2015)

Intel 730 Series 2.5" 480GB SATA 6Gb/s MLC Internal Solid State Drive
(SSD) SSDSC2BP480G4R5 (12/3/2014)(The Intel SSD is a carryover from
the drive in my previous system... do SSD's slow down? Computer
Management says it's 446.668 GB with 288.85 GB free)

I also have 2 3 TB spinning drives for data and backups. I don't think
either one is a factor in this, as they've been in the system long
before this started.