The tug of war over 3PAR has picked up its pace.

Thursday morning Dell upped its offer for the virtualized storage house to $24.30 a share, a scant 30 cents better than HP's surprise offer of $24 on Monday, but still roughly $1.53 billion, up significantly from the $1.15 billion that 3PAR accepted from Dell last week.

Thursday afternoon HP went to $27 a share, say $1.8 billion, 11% more than Dell.

Dell now has to decide whether to raise again. It's got perpetual matching rights.

Dell said Thursday morning that 3PAR had accepted its amended offer and that if the obscure little company walks away this time it's going to cost its suitor $72 million, up from the $53.5 million termination fee in their original agreement.

HP and Dell are chasing the unprofitable $200 million-a-year 3PAR for its cloud potential.

Wall Street expected HP to counter because at $26 and change at Thursday's close 3PAR's stock price remained above Dell's $24.30 offer. It has now hovering close to $28 in after-hours trading. The Street frothily speculated this week that the bidding could go to $29 a share according to a Reuters survey.

The guy in charge of HP's servers and storage, David Donatelli, said in a statement,"Our revised proposal offers superior value to 3PAR's shareholders, while maintaining our disciplined approach to only pursuing acquisitions that we believe will strengthen our portfolio and create long-term value for our shareholders. Not only is our offer superior to Dell's proposal, HP remains uniquely positioned to execute on this combination given the number of synergies between the two companies."

According to the story 3PAR told the SEC the other day HP, thinly disguised in the narrative as the unidentified "Company B," was actually the first company to make an acquisition offer. 3PAR didn't say what HP was willing to pay back on July 23 only that it was less than the $18 a share Dell eventually put on the table. The rejected HP was given an opportunity to improve on Dell's number but walked away on August 1. That was just about the time that the Mark Hurd crisis was coming to a head in HP's executive suite. Hurd was out August 6.

3PAR says Dell originally tried to hold its costs down to $15-$17 a share cash and wouldn't go to the $18.25 3PAR asked for on July 31 to negotiate exclusively.

See its SEC filing here. The chatty stuff starts on page 19. A Company A and a Company C also make brief appearances. One of them is generally believed to be Oracle. The Wall Street Journal thinks the other one was NetApp. The Register for some reason thinks it was Cisco.