os x 10.10.3 installed and wifi slowed down

The same 😟

MacBook Pro 13" (mid 2012)

Try restarting your WiFi Router and then, restart all your devices that are on your WiFi network.

Didn't work 😟

I believe (if you signed up for the iCloud iPhoto library) the internet and/or iCloud has been overwhelmed by the surge. All your photos must be uploaded, if iCloud is overwhelmed by demand, maybe its like a hack attack. In any case, I had a similar problem with timeouts, or slow connections. I just shut off my iCloud photos, and its been working fine since.

" Didn't work 😟"

But, maybe..

Hmmm...looks good from 15 min!

Thank you Apple! This is how customer care should look: before upgrading to 10.10.3 I had wifi issues on just one computer (Pro retina 13 inch from 2013). Now the story changed: I have issues on ALL my laptops (Pro retina 13 inch 2013, Pro retina 13 inch 2014 and Pro 13 inch 2011). Good job! Thus everyone can now enjoy the wonders of your insane innovation process.

BTW: Your innovation looks really well. Shame that in this innovation cycle you lost years ago the motto "it just works". I feel each and every day a beta tester on your RELEASE versions of your products. But I shall make you ca confession: I give you ONE MORE YEAR as an ultimatum and then it's WINDOWS which I will install on my Macs. I hope at WWDC 2015 you will show the public NOTHING NEW, you just patch the holes in your leaky OSX.

Please answer as many of the following questions as you can. You may already have answered some of them. In that case, there's no need to repeat the answers.

Back up all data before making any changes.

Have you restarted your router and your broadband device (if they're separate) since you first noticed the problem? If not, do that now and see whether there's any change.

If you connect to the the router with Wi-Fi, turn off Wi-Fi and then back on. Any change?

If you connect with Wi-Fi and you can also connect with Ethernet, do that and turn off Wi-Fi. Any difference?

If your browser is Safari, then from the Safari menu bar, select

Safari ▹ Preferences... ▹ Privacy ▹ Remove All Website Data

and confirm. If the Downloads button (with the icon of a downward-pointing arrow) is showing in the toolbar, click it and then click Clear in the box that appears. The download history will be removed. Any change?

Select the Extensions tab in the Preferences window. Turn all extensions OFF and test. Any better? If so, turn extensions back ON and then disable them one or a few at a time until you find the culprit.

If you're running OS X 10.9 or later, select the Advanced tab in the Preferences window and uncheck the box marked

Stop plug-ins to save power

Any change?

Quit and relaunch the browser. Any change?

Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”

While logged in as Guest, you won’t have access to any of your documents or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this behavior; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.

Test while logged in as Guest. Same problem?

After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.

*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.

Are any other web browsers installed, and are they the same? What about other Internet applications, such as iTunes and the App Store?

If other browsers and Internet applications are also affected, follow these instructions and test. Any change?

If Parental Controls is active for any user, please turn it off and test. Any change?

Open the iCloud preference pane and uncheck the boxes marked Safari and Photos, if they're checked. Any change?

Are there any other devices on the same network that can browse the Web, and are they affected?

If you can test Safari on another network, is it the same there?

I've been trying to fix this issue for the past couple of weeks. Talked to apple support three times and they finally admitted that Yosemite has had this issue since 10.10.1. 10.2 and 10.3 were supposed to fix the issue, it even says it on the upgrade description "improves wifi connectivity" or something like that. The last guy I talked to said he was going to talk to a senior advisor and that they would get back to me. My ipad and iphone have no issues connecting to my network only my mac mini and it happened right after I upgraded to Yosemite. I did some research and found this;

https://medium.com/@mariociabarra/wifried-ios-8-wifi-performance-issues-3029a164 ce94

alfrescotunes,

Did that link actually help in your case ?

I'm having a similar, though not exactly identical issue, after updating to 10.10.3. Now whenever my MacBook Pro (Retina, Mid 2012) is on my home network, not only does its own ability to connect to the Internet cease to function, save for very brief moments every few minutes, but it literally nukes every other device on my network from connecting to the Internet. Taking my MacBook off of the network restores Internet functions to every other device almost instantaneously. Extremely frustrated right now, as the only way to get my MacBook online is via tethering it to my phone's LTE connection.

I had same problem. Turned off Magic Mouse and wifi working. Of course, Magic Mouse is now disabled.