Apr 20, 2011 09:06 GMT  ·  By

Reports from three different sources across the U.S. and Asia say that Apple’s current iMac stock is getting depleted, in anticipation of a refresh.

Indeed due for some hardware upgrading, iMac supplies have never been so constrained, according to 9to5mac citing the people familiar with this matter.

These sources, all in different countries from North America and Asian, say that supplies for the current iMac models have tightened “significantly,” something that has never happened since their original introduction in late 2009.

These people say the most constrained parts making up the iMac are the graphics processors and hard drives.

Of course, shortages these days can also be attributed to the earthquake and tsunamis hitting Japan in March, which put several major component makers out of commission.

But the sheer number of tipsters chiming in to confirm there is something fishy going on with iMac supplies provides a good indication that a refresh is more likely.

The Asian source, for example, is telling the blog that 21.5 inch iMacs are actually very constrained, particularly the 3.06 GHz configuration - the entry level, $1,199 model.

The remaining other three models are also becoming constrained, this person reportedly said.

Additionally, Apple fans curious to learn about potential Mac mini and White MacBook refreshes have been told by the blog that there are still plenty of them floating around, despite them being very close to discontinuation.

Back to the rumored iMac refresh, it is only reasonable to assume that Apple will upgrade its popular line of all-in-one desktop computers to include Thunderbolt I/O and Sandy Bridge processors, to bring them up to feature parity with the recently refreshed MacBoook Pro line.

Such an announcement could come as early as next month, or at WWDC 2011 (June 6) the latest.