Truth to Monoprice's claims that AVRs add significant resistance to HDMI signals?

You need a certified High Speed cable (or really 5 high speed cables). Make sure of the cable's certification but other than that you should be free and clear to buy any brand or gauge.

It is true that the thicker the cable the more likely it will work for high speed signals over long distances. But, once it is truly certified for high speed the extra thickness doesn't really matter.

Lots of threads in this forum about Redmere. Very useful if going over 25 feet.

Sounds like they made it up on the spot.

Are you sure? I get audio drop-outs at times with my current HT setup that includes three devices hooked up to a Sony AVR (Comcast HD Cable STB, PS3, and Xbox 360) and the AVR is connected to a Samsung LED-LCD. I'm currently using high-speed hdmi cables that are much thinner than 24 AWG (probably 28 AWG).

Also, it seems the audio drop-outs/skips happen more in "Bitstream" mode on my slim PS3 than in "Linear PCM" mode while setting the Cable STB to "Pass Through" fares better than "Auto" mode.

I'll be getting RedMere HDMI cables soon to replace the existing ones since I've tried 24 AWG cables and those were too heavy and rigid and actually caused more audio drop-outs and the occasional video drop-out too (probably due to the cables being bent too much and the connections moving in the ports due too the heavy weight of the cable and the rigidness causing the cable to pull on the connectors/ports at an angle).

Monoprice told me the following in a chat with tech support:

TS - Daniel : in regards to your question, the 28awg cable isn't recommended to be used with receivers
TS - Daniel : we'd recommend either 24awg hdmi or redmere cables
me: I'm actually using these right now (http://www.monoprice.com/products/product.asp?
c_id=102&cp_id=10240&cs_id=1024004&p_id=3662&seq=1&format=2)
me: but there are too heavy and rigid for my setup
me: and the picture and audio cuts out every now and then
me: and it seems to pull at the connectors on my A/V devices
me: at an angle
TS - Daniel : if the weight is an issue, then we would recommend the redmere cables.
TS - Daniel : http://www.monoprice.com/products/product.asp?
c_id=102&cp_id=10255&cs_id=1025501&p_id=9168&seq=1&format=2&rep=daniel
me: what are redmere cables?
TS - Daniel : all the power of the 24awg, but with the lightness of the 28awg.
TS - Daniel : RedMere cables have a small chip in the HDMI connector, which boosts the performance of
the cable. The significant factor about RedMere cables is that they break the rules above about cable gauge
(AWG) and maximum lengths. RedMere cables can be much thinner than normal HDMI C ables and can reliably
handle High Speed (10.2 Gbps) signals to much greater lengths. HDMI C ables with RedMere chips can handle
full High Speed 10.2 Gbps signals to a maximum of 20 meters (65 feet)

Yes, AVR's don't add resistance.

I just got two of these yesterday for $17 a piece (on-sale) and they are unbelievably thin, even compared to the standard 28 AWG cables that came with some of my HDMI devices. So far, they are working perfectly for the most part and I only had one audio drop-out while watching 2 BD movies on my Slim PS3 in Bitstream mode (first movie had DD audio and second had DTS-HD MA audio... the latter one had an audio drop-out near the end of the credits). I haven't had any video drop-outs so far.

Could it be the AVR and/or PS3 that is causing the audio-drop-outs? I definitely had issues with the 24 AWG cables because they were so inflexible and heavy (constant audio drop-outs and occasional video drop-outs... never had the video drop-outs before using the 24 AWG cables). Any reason why the audio drop-outs are more common while using the PS3 in Bitstream mode (doesn't really happen much in Linear PCM mode... can't remember the last time it did)?

Could also be the laser in the PS3 or a delayed cycle in the PS3. When you repeated that section of the movie, did the audio drop-out reoccur?

didn't try replaying it, next time it does I will

another thing that comes to mind regarding the 24 AWG cables is that they were just long enough for my setup and so they needed to be bent a lot whereas the RedMere ones have plenty of slack and are bent far less as a result

Bending an HDMI cable - particularly sharp bends - is a known way to increase the likelihood of bit errors. So decreasing the amount of bending could lead to better data quality (everything else being equal).