It may be time to order that server upgrade or tweak those heavy, slow loading landing pages used for arbitrage or other affiliate led campaigns.
Not only will they hurt your conversions but it appears that Google are set to penalise landing pages which are slow to load giving them a lower Quality Score and hence a higher minimum bid price in an effort to improve the user experience.
The change could mean that affiliates conducting direct to merchant CPA search activity could have campaigns affected where for once they have no direct control over their quality score and consequently their campaign perormance.

To recap the Quality Score set for an affiliate or any SEM is determined by a combination of many factors including a keyword's clickthrough rate (CTR), the relevance of the keyword to its ad group, your accounts historical performance and your landing page quality.
The landing page quality can be overlooked. Google bots reguarly visit landing pages attempting to determine relevance, uniqueness and quality. They look at how many links are on the page, how you use those links and how easy your site is to navigate.
"The quality of information collected will affect your account performance in the future. Landing pages with useful, informative content related to your keywords and ad text are considered to be of higher quality and will receive higher quality scores. This may mean lower minimum cost-per-click bids (CPC bids) for your ads. (The inverse is also true - poor quality landing pages will receive lower quality scores.)"
Adwords users will shortly see a load time grade for each keyword and its associated landing page, either; This page loads slowly or No problems found.
If you get the first message don't panic here are some tips from adwords on how to decrease your load time:
I'm also hoping Google give adequate allowance for affiliate network and other tracking redirects in their alogrithm.
If you do get a penalty Google say that they will regualry send a bot to your landing page (around once a month) and its possible your GQC will improve over time.
You can find a wealth of information over at the Google adwords help centre
If you spend any money on adwords, I thoroughly reccommend you spend time to read it!
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Whatever next will they come up with to increase minimum bid. Pink? "Sorry Mr Advertiser but the quality score has been reduced because you have pink on your site, therefore we are whacking you with a £5 minimum bid"
Why is that Ebay can appear on completely irrelevant terms such as 'frozen embryo' and not be hit by a high minimum bid, but other advertisers have to pay astronomical min bids for 100% relevant terms
Good posting - there is certainly plenty to think about at the moment...
I was also in favour of their other recent change to give a quality score to the landing page based on W3C standards etc.
1) Sign in to Webmaster Tools with your Google Account login
2) Click your site if you see it on the page. If not, type in the URL of your website in the Sites field and click Add Site.
3)Select Tools in the sidebar.
4)Click Set crawl rate. Note that you'll need to have verified your site before you can do so.
5)The third graph will show your site's average load time.
My average is 1.2 secs so I'm hoping that's fast enough.
Google states: 'the amount of time it takes for a user to arrive at your functional landing page after clicking your ad.' - so I would presume PPC via AF will be more expensive!?
Joe
www.fourthewin.com
I have suspected this for a while and we pay a fair amount to make sure we have good hosting.