What browser are you using? Cox just upgraded my Ultimate to 150/20 too (It's only $99.99 here, it was 94.99 before the upgrade)... I'm still only getting 50 Mbps. But I know my connection is on fire fast right now. I download from Giganews I get 11.5 MB/s which is 92 Mbps. ... to achieve that however I have to open 50 connections. TestMy.net is not a multithreaded speed test. And trust me... you don't need it to be. I've regularly seen over 200 Mbps from thousands of miles out from the server. When you test elsewhere they multithread the test, they also often test you automatically on a server that's too close to you to be a true test of your speed OUT to the Internet. Your Internet isn't being served from within your city or state... why should you test it there? (my opinion but many agree). It ends up making connections look better than they might actually be. I've made this test to try to keep ISPs honest and consumers informed.
... I'm on the same package as you man. I'm not seeing 150 Mbps either, anywhere... TestMy.net's results are just more pronounced than other tests out there........ that's because it's showing you that you AREN'T getting what they advertise. Blatantly. I'm seeing about half of the advertised upload. Confirmed by uploading to various sites including YouTube... actually often got worse results than my upload speed tests here. Don't get me wrong, the connection is fast... but it ain't no 150/20. Cox is definitely the best game in town so I'm not going to complain about it either. The competition in Phoenix in CenturyLink... who HAS to still be digging their asses out of the rats nest of twisted pair that US West left behind from before Qwest came in and tried to clean it up. I opened one of their pedestals by mistake (when I was a cable tech)... I took one look at it and thought to myself, "F*$& THAT JOB!" ... seriously it looked like tens of thousands of twisted pair with no rhyme or reason, you definitely needed a toner to do that job. And they're still running Internet through that crap, no wonder they can't get over 40Mbps still and half the people that want that are told, "Sorry, not in your area... we have 12 Mbps in your area." BAH HA HA, it's 2013 and the competition has 150/20Mbps ....... wait ... or do they. -- even if Cox was only 40 Mbps it would STILL be better than DSL. Unless it's fiber to the house DSL the latency on coax is far superior. Way more stable connection in my experience. DSL pissed me off, felt jittery in comparison. Not nearly as smooth. Plus D5L6UY doesn't have the same ring to it as CA3LE6UY.
Every other package I've upgraded to in the past has performed over what they state. This time it didn't even feel like an upgrade (was 50/5 before), except when I multithread on Usenet or torrents. I'm convinced that I'll never see that speed on a single file download... ever. But other speed tests out there make it seem like it would get close... it won't. And trust me it's not for lack of bandwidth on TestMy.net's end, the home server is a monster with 2000 Mbps of connectivity in what many consider to be Softlayer's most well connected datacenter... It's also not for lack of the test technology being able to do it, like I said before there are tons of people including myself who've seen well over 200 Mbps. What is it then? I think it's our host limiting us, shaping the way our bandwidth can be used. It's called traffic shaping or packet shaping ... they're doing a form of bandwidth throttling. This is the first time I've seen it first hand on my own connection and I haven't fully confirmed this with anyone from Cox, but I will. I haven't worked for them for like 9 years but I still have good friends there that can give me the inside scoop on this if they know anything. If I find anything I'll write something about and pin it (means it will stay at the top of the forum) in General Discussion.
Cheers! -- thank you for your patronage, I hope you like what I've built.