As stated in the title, I have an HP DV9933CL with the 4965AGN under Win 7 Home Premium 64 bit (fully patched). I have the newest driver I can get from Intel, dated from 2010. n 188.8.131.52 or so. Up until a couple weeks ago I was using a Linksys WRT610N router and connecting on the 5GHZ band from about 15 feet away through a ceiling.
As of a couple days ago, I'm on a replacement 4965 AGN. Under the first card, and under the WRT610N, reception was poor and very flaky. Gradually got worse. Since the WRT610N gave me trouble with other equipment, I replaced it with a Netgear N750 / WNDR4000 (latest firmware). Strong signal, but I got to the point where after several hours of viable connection the connection would hang completely. If I reset - combination of using Device Manager to disable and re-enable and turning off and on the wireless switch on the HP, I'd get a few minutes, maybe, of access, then it would hang again. HP sent me a replacement 4965AGN which has been in use for a few days.
Now, I seem to get a better signal, good behavior for a while. If I come back to the PC 24 hours or so after I established the connection, I'm hung again. I can reset it as described above, and it seems to work normally another up to 24 hours. Connect speeds according to Win 7 ranging from 240 to 300 MBPS most of the time, usually 243 or 270.
I only have the driver installed (not the added management software at this time). Settings;
N channel width for 5.2 band - Auto
N mode enabled
ad hoc G 11
ad hoc qos wmm disabled
fat channel intolerant disabled
mixed mode protection cts to self enabled
roaming aggr low
transmit power highest
wireless mode abg
Computer cannot turn off wifi card to save power (reccomended by HP)
Most of the time I'm the only 5ghz user in my area for wifi. Yes, I do have cordless phones, but no signs of interference from them or from microwave oven.
Actual viable bandwidth - I use tools like speakeasy.net/speedtest to check my cable system - 60mbps download, 8 upload.
I've heard rumors that the current Intel driver doesn't work properly under Win 7, or Win 7 64 bit. Just rumors, no facts. I'd upgrade to a newer (full height) wifi card; the 5300 Ultimate sounds nice, but I've heard that HP has a bios whitelist that limits me, for N, to the 4956AGN. Either way, while 450 mbps wifi would be nice, I'd be happy if the card just worked properly without me constantly having to reset it or have to plug in wired to my LAN.