Citrix HDX better than PCoIP?

我的答案是肯定的。

在VDI市場上的競争來看，主流的隻有兩家Citrix XenDesktop和VMware View。而一直以來，XenDesktop的使用者體驗要大大優于View，但是随着View版本的不斷更新，View所使用的PCoIP協定性能也在提升。于是，關于兩家在VDI上的體驗，誰更優的讨論，也開始變得激烈，更有人僅僅為了結果而制作了視訊。

最開始Gartner分析公司，項目研究副總裁Chris Wolf說，Citrix HDX遠端桌面協定（ICA）在200ms的公網場景要優于high-latency。

對此VMware的 Scott Davis, CTO of the End User Computing business unit ，回應了此事：

...VMware View 4.5 with and PCoIP are configured out of the box to provide the richest LAN experience. There are several important parameters that can be adjusted to optimally tune the protocol for WAN conditions and specific usage scenarios. For WAN conditions it can be very helpful to adjust the display frame rate, p_w_picpath quality and min/max bandwidth settings. As an example, the default frame rate with PCoIP is 30. This can be safely cut down to 12 frames per second for WAN usage resulting in less bandwidth consumption and a better experience in many such circumstances...

針對Davis所講，可能view能夠降低幀率到12幀每秒，但是有使用者測試發現，可能會導緻眼部疲勞，具體參見：

http://www.searchvirtual.com.cn/showcontent_45245.htm

…Similarly, there are settings for bandwidth; maximum bandwidth can be used to constrain peak consumption to avoid starvation of other users, while minimum bandwidth can be used to avoid poor desktop performance due to congestion… …One other thing, the ××× Chris used was a Vyatta open source L2TP/IPsec ×××. There are numerous ways to configure such ×××’s, however PCoIP utilizes UDP for the graphics packets and optimizes parallelism and retransmits at the higher layers of the protocol. Hence we recommend using a ××× technology that support UDP packets natively, not to tunnel the UDP traffic over TCP/IP as doing so will typically cause responsiveness issues

Davis可能不願意承認Wolf所說的關于Citrix在200ms的延遲情況下更好的說法，但是他接下來又說了，200ms的公網環境，畢竟是小衆場景，可以看出，間接承認了在高延遲情況下的劣勢。