I found this saved as I logged in to reply. So I will start with this since it might fulfill a "purpose". . .
Screen Flicker is old. I have it on my early 2008 where they had a 4 year extended GPU replacement, but the previous owner of my MBP didn't know of it and never had the GPU replaced. Now it's my problem and it's not hilarious.
And on with what I have to say now . . .
After having no issues whatsoever from March of 2013, when I got this used Early 2008 17" MBP running Mountain Lion 10.8.2, to July and then all of a sudden having to deal with this on and off since, I can confirm that it is not a Mvrx issue, but existed in Snow Leopard also. Although it does not affect any other Apple device nor any other device at all. Last week I had my main tower lose a power supply and until I could get a replacement shipped in, I set up my Early 2008 laptop running SL Server, Mvrx 10.9.4 and 10.10 (Public Seed), far better processor, to work off of which has a line of sight to the router. Since all of my software are workhorse versions they would only run in SL Server. What an experience, my tower has 3 20" monitors and this 17" laptop is a trip. I noticed right off the top that there were no WiFi issues all of a sudden and left it at that to get a ton of work done. After needing to send off this work to output vendors I started to have WiFi issues. At that time I was running the second to the latest version of DD-WRT on a Netgear R6300v2, replacement for a "defective" R6300v1. The router probably is not at fault at all. Most everything sent as needed, but a couple stragglers needed to be sent via hardwire. After that was all over I started to play with settings in the router and different versions of firmware. Oh and the day before I lost the tower my Internet speed tripled. So I have a really good connection, said to be getting even better here soon when it will be doubled again, and was wondering why I wasn't enjoying it over WiFi. So as I said I have played with several version of DD-WRT and am now back at the OEM latest version. With every change of settings or firmware I could see a definite pro or con change in the way WiFi would work. Last night after trying one speed setting for a day and it tubing, I set it to the next, 1300Mbps, and my WiFi jumped to 270Mbps where it had been while I was not having any problems. But alas, it was not to be long lasting. Now it's vacillating between 0 and 130. At 104 as I type, oops now at 38, 59, 65, 52, 13, 104, 13, 7, 13 . . . I have also found, with my machine, that a start from sleep and sometimes restart can gain the connection. I can almost always depend on getting a connection after sleep no matter how much garbage the OS puts me through prior to. Not so much reboots. That even includes: the "no hardware installed" message, repeated unnecessary log ins, plain drops and whatnot. One thing though, this machine when it drops the connection really tries to reconnect on its own to the point of being obnoxious about it. And that all started after the installation of 10.9.4. One thing though, if it is indeed the OS that is the culprit, it leaves its mark on all OS's installed on the machine. So with that I am drifting to think it's a hardware issue, that once provoked, it's everlasting.
To me it seems as if the software is corrupting the hardware or putting a great deal of influence on it. And it's not new as of Mvrx and affects machines as far back as my Early 2008 model. If it does pan out to be hardware, which wouldn't surprise me, it's going to take a chunk out of the notorious Apple Billion Dollar reserves. But I wouldn't be surprised if this problem was a hypersensitivity on the OS's part to a multitude of variations in the real world that Apple has long since needed to address. Just my observations over the past year and a half.
