Sluggish performance within Windows 7/10 VDI session (Non network related!)

I’ve come across this now with multiple customers. Most of the time it’s showing up when people are moving to windows 10, after experiencing poor performance with W7 desktop VMs and as part of the migration process, they buy all new tin.

They experience sluggish responses when opening various apps and for example with IE, it’s painfully obvious that something is wrong. It will spike the CPU to a high percentage, take quite a while to open, then the CPU will drop and it’ll be OK for browsing until more tabs are opened and similar behaviour will occur.

When this occurs, I always ask if there’s any resource pools set, any QoS or similar on the storage and so on, but generally, I know there isn’t. vSphere monitoring will show that everything is OK, so will anywhere you look within Horizon and vROPs. I’ll ask if the physical hardware has power management/saving on within the BIOS and I usually get the following answers:

“Oh, I’m sure it’s been turned off, but I didn’t build the servers”

“Yep, no power management, vSphere says so.”

“I don’t know. How do you even do that?”

“I’ve asked and they say it has been.”

Every time. Every. Time. 

It can be difficult to definitely show that this is the source of the problem when everything you have access to says it all should be OK, plus people also have many different levels of experience with these things. I came across it about 7 years ago when the company I worked for had a mix of Dell and HP servers and being a PC gaming enthusiast, I was always trying to eke out as much performance of a PC as I could, so I tried to do the same with servers – no overclocking though! So power saving settings would be the first thing to get turned off!

So if you’re experience similar problems, with apps spiking the CPU, being sluggish, then the CPU dropping, check your physical hardware to make sure power management isn’t set to power saving, it’ll save you a whole load of heart ache! This also applies to Citrix as well.

If you need proof of this, or want to check it, there’s various tools, but I always check using Systrack – we have a tool as part of the suite called Resolve, which allows for in-depth analysis of specific machines (as well as the ability to compare to other machines/groups) and this will show straight away if a machine is being throttled, or has memory ballooning. Throttling can also show if a CPU is overheating and the BIOS throttles it back to avoid shutting down – many a place have thought they need new machines, or new CPUs, but no, they simply need to get those dusty fans cleaned out!


May show up a little bit too small for some screens, but what you’d see, is the CPU is throttled to 66%. The CPU usage is low, but due to the throttling, the Thread count and interrupt per seconds are high. The CPU should be 100% or even higher with some modern CPUs, but unless you’re really trying to save some power… You don’t want it lower than 100%

What’s also interesting, is when people go back to the older servers with Windows 7 on and realise that the poor performance throughout, was also due to the power management not being turned off… as a fair few manufacturers ship hardware with this as default…

Device Class GUIDs

You wouldn’t believe it (well you might if you’re here), but there’s times when you really, really need to go digging about in windows and need Device classes – especially when faffing around with legacy hardware, or *shiver* printers! I hate PRINTERS!

Device Class Class GUID Notes
Battery Devices Battery {72631e54-78a4-11d0-bcf7-00aa00b7b32a} This class includes battery devices and UPS devices.
Biometric Device Biometric {53D29EF7-377C-4D14-864B-EB3A85769359} Starting with Windows Server 2003, this class includes all biometric-based personal identification devices.
Bluetooth Devices Bluetooth {e0cbf06c-cd8b-4647-bb8a-263b43f0f974} Starting with Windows XP SP1, this class includes all Bluetooth devices.
CD-ROM Drives CDROM {4d36e965-e325-11ce-bfc1-08002be10318} This class includes CD-ROM drives, including SCSI CD-ROM drives. By default, the system’s CD-ROM class installer also installs a system-supplied CD audio driver and CD-ROM changer driver as Plug and Play filters.
Disk Drives DiskDrive {4d36e967-e325-11ce-bfc1-08002be10318} This class includes hard disk drives. See also the HDC and SCSIAdapter classes.
Display Adapters Display {4d36e968-e325-11ce-bfc1-08002be10318} This class includes video adapters. Drivers for this class include display drivers and video miniport drivers.
Floppy Disk Controllers FDC {4d36e969-e325-11ce-bfc1-08002be10318} This class includes floppy disk drive controllers.
Floppy Disk Drives FloppyDisk {4d36e980-e325-11ce-bfc1-08002be10318} This class includes floppy disk drives.
Hard Disk Controllers HDC {4d36e96a-e325-11ce-bfc1-08002be10318} This class includes hard disk controllers, including ATA/ATAPI controllers but not SCSI and RAID disk controllers.
Human Interface Devices (HID) HIDClass {745a17a0-74d3-11d0-b6fe-00a0c90f57da} This class includes interactive input devices that are operated by the system-supplied HID class driver. This includes  devices that comply with the USB HID Standard and non-USB devices that use a HID minidriver. For more information, see HIDClass Device Setup Class.. (See also the Keyboard or Mouse classes later in this list.)
IEEE 1284.4 Devices Dot4 {48721b56-6795-11d2-b1a8-0080c72e74a2} This class includes devices that control the operation of multifunction IEEE 1284.4 peripheral devices.
IEEE 1284.4 Print Functions Dot4Print {49ce6ac8-6f86-11d2-b1e5-0080c72e74a2} This class includes Dot4 print functions. A Dot4 print function is a function on a Dot4 device and has a single child device, which is a member of the Printer device setup class.
IEEE 1394 Devices That Support the 61883 Protocol 61883 {7ebefbc0-3200-11d2-b4c2-00a0C9697d07} This class includes IEEE 1394 devices that support the IEC-61883 protocol device class.The 61883 component includes the 61883.sysprotocol driver that transmits various audio and video data streams over the 1394 bus. These currently include standard/high/low quality DV, MPEG2, DSS, and Audio. These data streams are defined by the IEC-61883 specifications.
IEEE 1394 Devices That Support the AVC Protocol AVC {c06ff265-ae09-48f0-812c-16753d7cba83} This class includes IEEE 1394 devices that support the AVC protocol device class.
IEEE 1394 Devices That Support the SBP2 Protocol SBP2 {d48179be-ec20-11d1-b6b8-00c04fa372a7} This class includes IEEE 1394 devices that support the SBP2 protocol device class.
IEEE 1394 Host Bus Controller 1394 {6bdd1fc1-810f-11d0-bec7-08002be2092f} This class includes 1394 host controllers connected on a PCI bus, but not 1394 peripherals. Drivers for this class are system-supplied.
Imaging Device Image {6bdd1fc6-810f-11d0-bec7-08002be2092f} This class includes still-image capture devices, digital cameras, and scanners.
IrDA Devices Infrared {6bdd1fc5-810f-11d0-bec7-08002be2092f} This class includes infrared devices. Drivers for this class include Serial-IR and Fast-IR NDIS miniports, but see also the Network Adapter class for other NDIS network adapter miniports.
Keyboard Keyboard {4d36e96b-e325-11ce-bfc1-08002be10318} This class includes all keyboards. That is, it must also be specified in the (secondary) INF for an enumerated child HID keyboard device.
Media Changers MediumChanger {ce5939ae-ebde-11d0-b181-0000f8753ec4} This class includes SCSI media changer devices.
Memory Technology Driver MTD {4d36e970-e325-11ce-bfc1-08002be10318} This class includes memory devices, such as flash memory cards.
Modem Modem {4d36e96d-e325-11ce-bfc1-08002be10318} This class includes modem devices. An INF file for a device of this class specifies the features and configuration of the device and stores this information in the registry. An INF file for a device of this class can also be used to install device drivers for a controllerless modem or a software modem. These devices split the functionality between the modem device and the device driver. For more information about modem INF files and Microsoft Windows Driver Model (WDM) modem devices, see Overview of Modem INF Files and Adding WDM Modem Support.
Monitor Monitor {4d36e96e-e325-11ce-bfc1-08002be10318} This class includes display monitors. An INF for a device of this class installs no device driver(s), but instead specifies the features of a particular monitor to be stored in the registry for use by drivers of video adapters. (Monitors are enumerated as the child devices of display adapters.)
Mouse Mouse {4d36e96f-e325-11ce-bfc1-08002be10318} This class includes all mouse devices and other kinds of pointing devices, such as trackballs. That is, this class must also be specified in the (secondary) INF for an enumerated child HID mouse device.
Multifunction Devices Multifunction {4d36e971-e325-11ce-bfc1-08002be10318} This class includes combo cards, such as a PCMCIA modem and netcard adapter. The driver for such a Plug and Play multifunction device is installed under this class and enumerates the modem and netcard separately as its child devices.
Multimedia Media {4d36e96c-e325-11ce-bfc1-08002be10318} This class includes Audio and DVD multimedia devices, joystick ports, and full-motion video capture devices.
Multiport Serial Adapters MultiportSerial {50906cb8-ba12-11d1-bf5d-0000f805f530} This class includes intelligent multiport serial cards, but not peripheral devices that connect to its ports. It does not include unintelligent (16550-type) multiport serial controllers or single-port serial controllers (see the Ports class).
Network Adapter Net {4d36e972-e325-11ce-bfc1-08002be10318} This class includes NDIS miniport drivers excluding Fast-IR miniport drivers, NDIS intermediate drivers (of virtual adapters), and CoNDIS MCM miniport drivers.
Network Client NetClient {4d36e973-e325-11ce-bfc1-08002be10318} This class includes network and/or print providers.
Network Service NetService {4d36e974-e325-11ce-bfc1-08002be10318} This class includes network services, such as redirectors and servers.
Network Transport NetTrans {4d36e975-e325-11ce-bfc1-08002be10318} This class includes NDIS protocols, CoNDIS stand-alone call managers, and CoNDIS clients, in addition to higher level drivers in transport stacks.
PCI SSL Accelerator Security Accelerator {268c95a1-edfe-11d3-95c3-0010dc4050a5} This class includes devices that accelerate secure socket layer (SSL) cryptographic processing.
PCMCIA Adapters PCMCIA {4d36e977-e325-11ce-bfc1-08002be10318} This class includes PCMCIA and CardBus host controllers, but not PCMCIA or CardBus peripherals. Drivers for this class are system-supplied.
Ports (COM & LPT ports) Ports {4d36e978-e325-11ce-bfc1-08002be10318} This class includes serial and parallel port devices. See also the MultiportSerial class.
Printers Printer {4d36e979-e325-11ce-bfc1-08002be10318} This class includes printers.
Printers, Bus-specific class drivers PNPPrinters {4658ee7e-f050-11d1-b6bd-00c04fa372a7} This class includes SCSI/1394-enumerated printers. Drivers for this class provide printer communication for a specific bus.
Processors Processor {50127dc3-0f36-415e-a6cc-4cb3be910b65} This class includes processor types.
SCSI and RAID Controllers SCSIAdapter {4d36e97b-e325-11ce-bfc1-08002be10318} This class includes SCSI HBAs (Host Bus Adapters) and disk-array controllers.
Smart Card Readers SmartCardReader {50dd5230-ba8a-11d1-bf5d-0000f805f530} This class includes smart card readers.
Storage Volumes Volume {71a27cdd-812a-11d0-bec7-08002be2092f} This class includes storage volumes as defined by the system-supplied logical volume manager and class drivers that create device objects to represent storage volumes, such as the system disk class driver.
System Devices System {4d36e97d-e325-11ce-bfc1-08002be10318} This class includes HALs, system buses, system bridges, the system ACPI driver, and the system volume manager driver.
Tape Drives TapeDrive {6d807884-7d21-11cf-801c-08002be10318} This class includes tape drives, including all tape miniclass drivers.
USB USB {36fc9e60-c465-11cf-8056-444553540000} This class includes USB host controllers and USB hubs, but not USB peripherals. Drivers for this class are system-supplied.
Windows CE USB ActiveSync Devices WCEUSBS {25dbce51-6c8f-4a72-8a6d-b54c2b4fc835} This class includes Windows CE ActiveSync devices.The WCEUSBS setup class supports communication between a personal computer and a device that is compatible with the Windows CE ActiveSync driver (generally, PocketPC devices) over USB.
Windows SideShow SideShow {997b5d8d-c442-4f2e-baf3-9c8e671e9e21} This class includes all devices that are compatible with Windows SideShow. This class is supported in Windows Vista and later versions of Windows.

System-Defined Device Setup Classes Reserved for System Use

Device Class Class GUID Notes
Adapter Adapter {4d36e964-e325-11ce-bfc1-08002be10318} This class is obsolete.
APM APMSupport {d45b1c18-c8fa-11d1-9f77-0000f805f530} This class is reserved for system use.
Computer Computer {4d36e966-e325-11ce-bfc1-08002be10318} This class is reserved for system use.
Decoders Decoder {6bdd1fc2-810f-11d0-bec7-08002be2092f} This class is reserved for future use.
Global Positioning System GPS {6bdd1fc3-810f-11d0-bec7-08002be2092f} This class is reserved for future use.
Host-side IEEE 1394 Kernel Debugger Support 1394Debug {66f250d6-7801-4a64-b139-eea80a450b24} This class is reserved for system use.
IEEE 1394 IP Network Enumerator Enum1394 {c459df55-db08-11d1-b009-00a0c9081ff6} This class is reserved for system use.
No driver NoDriver {4d36e976-e325-11ce-bfc1-08002be10318} This class is obsolete.
Non-Plug and Play Drivers LegacyDriver {8ecc055d-047f-11d1-a537-0000f8753ed1} This class is reserved for system use.
Other Devices Unknown {4d36e97e-e325-11ce-bfc1-08002be10318} This class is reserved for system use. Enumerated devices for which the system cannot determine the type are installed under this class. Do not use this class if you are unsure in which class your device belongs. Either determine the correct device setup class or create a new class.
Printer Upgrade Printer Upgrade {4d36e97a-e325-11ce-bfc1-08002be10318} This class is reserved for system use.
Sound Sound {4d36e97c-e325-11ce-bfc1-08002be10318} This class is obsolete.
Storage Volume Snapshots VolumeSnapshot {533c5b84-ec70-11d2-9505-00c04F79deaf} This class is reserved for system use.