Vrámci nezávislého pohľadu na vec, aby som mohol byť čo najobjektívnejší, uvádzam pre objektívne vytvorenie si obrazu o vyššie uvedenom testovaní, vyjadrenie od spoločnosti VMware, ktorá sa testu vykonaného spoločnosťou MIERCOM nezúčastnila. Z tohoto dôvodu ich vyjadrenie k tejto problematike bude zobrazené v pôvodnom formáte a jazyku :
 
 
Background
VMware is aware of the Miercom report that was commissioned and paid for by Citrix. We did
not participate in the tests they ran, and don’t know how they set those tests up, how they
configured VMware View4, and how they arrived at some of their conclusions. We would gladly
welcome the opportunity to take part in unbiased, apples to apples comparison with Citrix.
As we’ve previously announced, VMware has sold more than 1M VDI seats and leads the virtual
desktop market. View 4 has experienced strong uptake since its release in Q4 2009 and
customers are reporting excellent results with their desktop virtualization implementations and
PCoIP – they like the superior user experience that comes with the industry’s only dynamic
bandwidth allocation, the ability to have a superior experience across rich media as well as
standard office applications, and the ability to enjoy this experience in both LAN and WAN
environments. Our customers are our best references – and we’d be happy to connect you with
them so you can hear from them first hand.
 
VMware Response
With regards to specific assertions made in the report, we note the following:
 
In a comparison of Virtual Desktop Infrastructure (VDI) implementations, Citrix XenDesktop 4 provided better overall performance when compared to VMware View 4
 
It appears that the Miercom report did not consider the image quality of office applications.
XenDesktop 4 uses lossy client side image caching compared to VMware View 4’s lossless
techniques, which favor the View 4 user experience.
Many customers insist on lossless image delivery – image compression artifacts are totally
unacceptable to them. The PCoIP protocol provides network efficient progressive image
refinement that builds the desktop image to a lossless image. As a result, View is consistently
chosen to deliver a high-quality desktop experience.
 
XenDesktop 4 used 64% less bandwidth than View 4 with PCoIP for typical tasks

In our testing, the Sysmark benchmark for View 4 used 40% less bandwidth when run on a
1Mbps network compared to running the same test on a 100Mbs network. However,
XenDesktop 4 used essentially the same bandwidth in both cases – pointing out the weakness
of a fixed quality system – Citrix cannot take advantage of additional network resources when
available. Miercom used 100Mbps as their ‘WAN’ for the single user test which skews the
results and is not a real deployment scenario.
Reminder – the PCoIP protocol dynamically adapts the image quality based on the available
network resources – thusly View 4 favors the best user experience when operating on an
unconstrained network. So using a single user session to measure bandwidth performance is
not a valid testing scenario. A more realistic scenario would be to compare View 4 to
XenDesktop 4 on a constrained network supporting multiple users – this would result in
significantly less bandwidth used by each View 4 session, while giving the best experience
possible for the concurrent users.
On the other hand, Citrix HDX uses a fixed quality (set by IT) that cannot adapt to available
network resources (even if more bandwidth becomes available) and does not allow them to
efficiently use/share the total bandwidth therefore not giving the best user experience.
Dynamic adjustments in display compression quality result in the best and most consistent user
experience for a given network environment. The PCoIP protocol will fairly share the bandwidth
across the active users for a given network segment.
 
Flash video was delivered with an average of 65% less CPU usage, 89% less bandwidth, and excellent Quality of Experience by XenDesktop 4 compared to View 4

Part of the strength of PCoIP is the fact that it adapts to the network. So, if you were to test a
single desktop, as an example running multimedia, then you would observe that PCoIP
consumed whatever bandwidth was available at the time. If bandwidth is available, it will use it
to deliver the highest quality experience. If bandwidth is restricted, as is recommended in
constrained environments, PCoIP "throttles down" to consume less bandwidth and is a “good
citizen” in the network. Our customers report that PCoIP has been game changing for them
and enables the delivery of a desktop environment that is secure, scalable, and easy to
manage.
For environments where bandwidth is a concern, PCoIP can be configured to limit the amount
of bandwidth it consumes. Customers have found they can limit bandwidth and still have a
strong user experience.
With regards to the flash video test, this is not an apples to apples comparison – since the tests
were conducted running FLASH redirection with an unrealistically high packet loss of 0.5 to 5%.
A correctly provisioned network will have packet loss of 0.1% or less which would result in
great video performance.
A 100Mbps “WAN” link is an unconstrained network environment (again, single user test on an
unconstrained network is not valid).
Finally, the PCoIP protocol has no reliance whatsoever on client side driver compatibility,
however that is not the case for Citrix’s Flash redirection (in addition to mandating a locally
installed Flash client, the Citrix solution also requires more powerful client hardware and
increases the operational cost of the client). Because the Citrix solution only works with Adobe
Flash they chose to ignore various other video cases – such as Microsoft Silverlight, Google’s
On2 etc. With the PCoIP protocol, current or future versions of Flash, QuickTime or other
CODECs/plug-ins will just work.
 
Overall, XenDesktop 4 uses system resources more efficiently and is capable of scaling more effectively

Enterprises have an investment in their networks and by not dynamically adjusting the user
bandwidth to take advantage of the available network resources real dollars are wasted and the
user experience is impacted.
Depending on multi-media redirection (MMR) solely does not provide real scalability. It does
not handle the case of common office applications and requires constant investment (by Citrix
and the resulting increased IT management) which translates to real cost to IT. It also does
not cover other video options like Apple Quicktime, Microsoft Silverlight, and Google’s On2
(expected to replace Adobe flash on Google websites including Youtube).
Interesting that Miercom/Citrix does not call out the management costs of HDX flash
optimization/redirection. In addition to requiring a more powerful (and costly) client, the client
media CODECs must be constantly updated as Adobe, Microsoft etc update their media
protocols.
Only VMware View 4 supports a true zero client on the desktop to provide the lowest operation
cost, highest security and future-proof scalability (supports any media or graphics).