The Open Industry Network Performance & Power Test for Cloud Networks Evaluating 10/40 GbE Switches Spring 2013 Edition from Lippis Enterprises dated July 2013 says nothing about a dynamic buffer pool for the G8264. The G8264 is reported next to the Arista 7050S-64 that also uses the Trident+ switch chip where dynamic buffering is described in detail. IBM appears to have decided that dynamic packet buffers were not interesting to their market segment -- so they didn't pay to have it tested. In 2013, the emphasis in the product manual is for data center applications like Fiber Channel over Ethernet. Fiber channel is more deterministic than Ethernet and dynamic buffering is not deterministic.

Earlier in the product life cycle IBM commissioned a competitive switch test by the Tolly Group in March 2011 that does report on buffering. Summarizing:

Switch 9216 byte packets Imputed buffer
IBM G8264 1000 packets 9.22 Mbytes
Arista 7148X 335 packets 3.09 Mbytes
Cisco 5548P 105 packets 0.97 Mbytes
Juniper EX4500 25 packets 0.23 Mbytes
Juniper EX4200 * 8 packets 0.07 Mbytes
HP 3800 * 25 packets 0.23 Mbytes
Cisco 3750-X * 1 packet 0.01 Mbytes
* Report from a different Tolly test (#211127) cites work from July 2011. The test was commissioned by Hewlett Packard and probably should not be compared directly with the others in the table. Some packet memory appears to have been held back in queues that were not used when the measurements were made.

Refer to the disclaimer at the top of page that says rumor, innuendo and extrapolation. Tolly attributes something more than 100 percent of the buffer is available for microbursts. That seems suspicious. The buffer imputed to the Cisco 5548 switch also exceeds the manufacturer's claims. Unlike other tests reported in this Tolly paper, there is no RFC that says how to measure microburst capability. Absent some real skullduggery, the relative results are probably useful.

Regardless of whether IBM might have a dynamic buffer control that I missed when I read the manual, the warning stands: Use of particular silicon is no guarantee of availability of a feature absent its presence in the switch data sheet or other documentation. Report from a for-hire tester of something not claimed in the data sheet is also probably not wise.